Firefox 3 was released just this June, and many Firefox fans believe the new version is clearly the best browser you can get. You can make it even better with free add-ons, which integrate directly into the browser and offer loads of useful new features.

Want to increase your security and privacy, synchronize bookmarks among multiple PCs, dress up Firefox tabs, juice up Google, and more? Then I've got the add-ons you need. These 15 great downloads make the world's best browser even better -- and, like Firefox itself, they're free.

[ Slideshow: What are InfoWorld's Paul Venezia's picks for the best general-purpose and developer Firefox add-ons? ]

Foxmarks Bookmark SynchronizerIf you use Firefox on more than one PC, you most likely spend a lot of time trying to keep their bookmarks in synch, or else you've simply given up the attempt. Otherwise, every time you add, delete, or edit bookmarks on one PC, you have to remember to make the same changes on the others. Not a pretty picture.

The Foxmarks Bookmark Synchronizer solves the problem. Install this tool on each of your PCs, and then, with a click or two, you can synchronize any changes. In fact, you don't even need to click because you can set the program to synchronize automatically.

The utility offers other benefits as well. Your bookmarks are automatically backed up to a server, so if for some reason you lose them on your PCs, you can always restore them. You can also log into the Foxmarks Bookmark Synchronizer Web site and edit your bookmarks directly there. In addition, if you're using someone else's PC, you can use your bookmarks straight from the Foxmarks server.

Download Foxmarks Bookmark Synchronizer | Price: Free

Secure LoginIf you often log into Web sites and forget or lose your password, Secure Login will be a great time-saver. It directly integrates with Firefox's password manager, and will log you into any Web site without you having to remember or look up the password. When you're on a page that requires a login, simply click the icon. Better yet, use a hot-key combination to log in faster.

The program also helps keep you safe online -- it prevents hackers from stealing your passwords by halting malicious JavaScript code. It also protects against other password dangers, such as cross-site scripting (XSS) attacks.

Download Secure Login | Price: Free

BugMeNotRegistering with a Web site often means making a deal with the devil. You give the site information such as your name, e-mail address, and potentially more private data such as your mailing address, phone number, and age. But what happens with that information? You may be inundated by spam, your name may be sold to mailing lists and advertisers, and possibly worse. But for many Web sites, if you don't register, you can't log in and use the site.

This add-on solves the problem. Go to a Web site, right-click in the user name or password field, and select BugMeNot. A valid user name and password will then be entered into the form. You can then use the site without having to register. The add-on works in concert with the BugMeNot Web site, which has many user names and passwords for multiple sites.

Download BugMeNot | Price: Free

Better Gmail 2From my point of view, Gmail has one primary drawback -- it gives you little that you can customize. Basically, what Google gives you is what you get and nothing more. This add-on changes that. It lets you customize Gmail in a variety of ways including skinning it to change its colors and appearance, customizing the sidebar (for example, hiding the spam count), adding HTML signatures automatically to your mail, and more.

Download Better Gmail 2 | Price: Free

Adblock PlusDoes it seem as if the Internet has become the equivalent of a digital Las Vegas with flashing neon ads wherever you look? Banner ads, ads that are placed willy-nilly, videos that start without your permission -- these are just some of the things can distract you and make pages load more slowly.

The answer? Adblock Plus. This add-on blocks just about any ad, but still lets you view the content you want. It claims to eliminate 99 percent of ads on the Web, and that just might be true. When you first start the program, you have your choice of filters to use. If you're the extremely adventurous type, you can try to build your own, but you'll be much better off picking one that already exists. If you browse primarily English-language sites, just choose the EasyList (USA) option. If a banner somehow manages to make it through, right-click it, select Adblock from the context menu, and you won't see it again.

Download Adblock Plus | Price: Free

Sage-TooLooking to keep up with your favorite blogs, news sites, and other fast-changing information resources? You need an RSS reader, which grabs feeds in RSS formats, then lets you browse through and read only what you want. Sage-Too, an update of the venerable Sage reader, makes subscribing to, managing, and reading RSS feeds exceptionally easy. When you're on a page with an RSS feed, click a button, and Sage will find the feed for you and subscribe to it.

The reader itself is very slick, and displays the feeds inside Firefox, including graphics. You'll see a summary of each posting; to get to the full posting, click it. It is also easy to reorganize and automatically update your feeds. Plenty of display options exist, as well.

Download Sage-Too | Price: Free

Google PreviewGoogle may be the best search tool on the planet, but it's still missing a very useful feature -- the ability to preview a site before you visit it. A simple text listing and site description usually isn't enough.

Google Preview adds such a previewing capability to Google search results by displaying a thumbnail image of each site to the left of its description. That way, you can better see whether it's a site you want to go to. The add-on also offers site thumbnails when you search using Yahoo.

Download Google Preview | Price: Free

CustomizeGoogleIf you're a big user of Google (and face it, who isn't?), you'll want to install this add-on. It customizes Google in just about any way you could imagine, and no doubt in many ways you couldn't. For starters, it will block Google's ads as well as Google analytic cookies (some people believe these cookies invade their privacy). Additionally, it anonymizes your Google user ID.

That's just the beginning, though. The extension adds links in your Google search results to other search engines, such as Yahoo and Ask.com, among others. It will also filter out search results from Web sites known to be spammers, and it will let you customize not just Google, but its various sites and features such as Gmail and Google News. In short, if you're a Google user and want to tweak the way Google works, make sure to download this one.

Download CustomizeGoogle | Price: Free

FireFTPThe FTP file transfer protocol, one of the earlier ways of transferring files on the Internet, has plenty of life in it. Since many ISPs these days limit the size of files you can transfer via e-mail, FTP remains a very effective way of sharing files.

Normally, you shouldn't try using your browser to transfer files via FTP -- that's not what browsers are built for. But with FireFTP, you get the best of both worlds with a full FTP client right within Firefox itself. It has plenty of useful features, including the ability to compare directories and subdirectories, keeping directories in sync, and automatically reconnecting and resuming file transfers.

You may become somewhat confused the first time you use the program. Don't expect to type in an FTP location into the Firefox address bar and get FireFTP to work, because it won't. Instead, you have to first open FireFTP by choosing Tools, FireFTP. Then create a new account for each FTP site from a button on the top left-hand side of the screen. After that, it's all straightforward.

Download FireFTP | Price: Free

NoScriptOne of the best things about the Web -- its interactivity -- is also the most dangerous. Tools like JavaScript, Java, and Flash Silverlight make the Web a far more entertaining and useful place. But they can be used in malicious ways as well. You'd like to run only the good interactivity, and leave out the bad. Sounds impossible, doesn't it?

That's exactly what NoScript does: It blocks all JavaScript, Java, and Flash Silverlight scripts by default, and then lets you allow them to be run on safe sites. As you browse the Web, a small icon runs in the bottom right of your screen telling you the status of NoScript. If any scripts are being blocked, you'll be shown details in a bar at the bottom of the page. To customize how scripts should be run on the site, click the icon, and you'll be able to allow scripts through from the site or block them -- permanently or temporarily -- along with other options.

Download NoScript | Price: Free

Video Download HelperVideo sites such as YouTube and others are certainly entertaining, and at times even useful. But there's one problem with them: You can't download videos to your PC to play them later. You have to revisit the site each time you want to see a video.

Video DownloadHelper does away with this limitation. It will let you download videos from YouTube and many other sites and store them on your hard disk, so you can watch them whenever you want. When you're on a site, all you'll have to do is click the Video DownloadHelper icon and save the video. You can also do the same for graphics and audio clips.

Some video and music files can be quite large, so the program gives you the option of not downloading files over a certain size. It can also work with any video converter program that you may have installed to convert videos to more useful formats.

Download Video Download Helper | Price: Free

ColorfulTabsThere's no two ways around it -- Firefox's tabs are just plain dull. A bit like the Model T, they come in any color you want as long as they're the same shade of gray. If you'd like to dress up your tabs and make it easier to distinguish among them, you'll want this simple extension. You can either stick with the default colors, or choose your own color for each tab. You can even have the program remember the color for each URL you visit. You can control more than just the basic color of each tab. You can also have the colors fade, and you can even put a background color on each.

Will this add-on change your browsing life? No. Will it make it more visually pleasing? Without a doubt, and that's enough reason to give it a try.

Download ColorfulTabs | Price: Free

WOT (Web of Trust)It isn't news that the Web is full of innocent-seeming sites harboring bad intentions: Sites that host spyware or malware. Sites that spam you. Sites that scam you. Sites that invade your privacy, or that children shouldn't view.

Unfortunately, there's no simple way to tell the good sites from the bad. WOT, however, acts as just such a screener. It rates every site for trustworthiness, vendor reliability, privacy, and child safety, and shows you the results using simple, instantly interpretable colored icons (red for bad, green for good). When you do a search in Google or another Web site, you'll see the icons and know what you're in for if you visit. You can also visit the WOT rating for each site to see why it was given its rating.

It offers other protections as well. When you visit a site with a red rating, you first get a big warning on your screen. That way, you can either navigate away or click through at your own peril. And when you're on any Web site, click the WOT button in Firefox, and you'll be shown details about the site's rating as well.

Download WOT (Web of Trust) | Price: Free

Mini Map SidebarGoogle Maps and other mapping services are among the most useful sites on the Internet. But they do have one inconvenience: You have to visit them to get their information. Wouldn't it be nice if you could get mapping information no matter where you were on the Web?

The Mini Map Sidebar does just that. Open it as a Firefox sidebar, then drag and drop address names or links to it, and a map of them will open right in the sidebar. You have your choice of map services, including Google Maps, Yahoo Maps, and others. You can then zoom in or out, get directions--in short, do pretty much anything you can do on the mapping site itself. In fact, you can do even more because Mini Map Sidebar includes some nice extras such as traffic information.

Download Mini Map Sidebar | Price: Free

All-in-One SidebarThe Firefox sidebar is one of the browser's more useful tools, but most likely one of its least used. It serves plenty of purposes -- you can browse your history and view your bookmarks there, for instance. And many add-ons, such as Sage-Too, use it as well.

This clever tool lets you quickly switch among all your sidebar panels, and gives you a great deal of information about your Firefox use. Want to see your entire download history in the sidebar? It can do that. It will also show you all of your add-ons with details about each, give you information on the current page you're visiting, and more.

If you don't regularly use the Firefox sidebar, give this add-on a try, and you might change your mind. And if you do use it regularly, this one will be a keeper.

Download All-in-One Sidebar | Price: Free

Last word: You can find all the files in this story in this Editor's Downloads Collection.

PC World is an InfoWorld affiliate.

Vista, thy name is bloat! The latest Windows packs a lot of code -- more than any version of Windows ever -- and some of it is just plain unnecessary. All of that excess code has a way of slowing down an operating system. You can regain some PC performance by removing unneeded features.

I've identified a dozen Vista features that you can turn off right now. Some are shiny baubles that slow down graphics performance, while others are optional utilities that hog memory when they shouldn't. A few can actually be quite useful, though they play a major role in bogging down your PC.

[ Get the analysis and insights that only Randall C. Kennedy can provide on PC tech in InfoWorld's Enterprise Desktop blog. And download our free Windows performance-monitoring tool. ]

Should you really turn off all of the following features right this minute? That depends on your computer, your work habits, and your tastes. (I've turned off only seven and a half on my PC, because while none of these features are required for Vista to function, some are still kind of nice and my computer is fast enough to handle them.)

Just to be on the safe side, make sure to create a restore point before you turn any of the items off. That way you can quickly return your machine to its present state should you decide that you don't like the change. To make a restore point, click Start, type sysdm.cpl, and press Enter. Choose System Protection, Create, and then follow the prompts.

I list the features in the order that would make them easiest to turn off. For instance, I've put features that you can remove in the same dialog box next to each other.

SidebarYou pay a heavy performance price for the analog clock, thumbnail slide-show viewer, and Microsoft-centric RSS news feed that dock in the Windows Sidebar. Turning the whole thing off gives you a big speed boost, especially at boot time.

To remove the Sidebar, right-click anywhere on the Sidebar and select Close Sidebar. Uncheck Start Sidebar when Windows starts, and then click OK.

AeroMicrosoft put a lot of Vista's visual enhancements under one technological and marketing umbrella: Aero. Among those features are the thumbnails of your windows that appear when you hover the mouse pointer over the taskbar, as well as the Flip 3D view you get by pressing Windows-Tab. Aero adds a little practicality and a lot of panache to the Vista user interface, and personally, I like it.

If your PC is underpowered or overloaded, however, Aero may be more trouble than it's worth. To turn it off, right-click the Windows desktop and select Personalize, Window Color and Appearance. In the resulting "Window Color and Appearance" dialog box, click Open classic appearance properties for more color options (if you don't see the option, that means Aero is already turned off). Select Windows Vista Basic and click OK.

Assorted Interface Beautification OptionsYou can save some additional clock cycles by turning off all or some of Vista's pretty interface options, not all of which are directly connected to Aero.

To see the options, click Start, right-click Computer, and select Properties. Click the Advanced System Properties link, the Advanced tab, and then the Settings button inside the Performance box.

You can uncheck all of the listed options by selecting Adjust for best performance, or you can simply uncheck the ones you don't care for. I unchecked Fade or slide menus into view, Fade or slide ToolTips into view, Show shadows under menus, and Slide open combo boxes. The rest I left on.

Remote AssistanceDon't worry about turning this item off if you run Vista Home (Basic or Premium). You don't have it. If you run Vista Business or Ultimate, though, you can use Remote Assistance to control one PC from another--a useful tool if you regularly provide tech support for a relative living far away.

On the other hand, if you're not providing long-distance support, or if you prefer a third-party remote-control program, Remote Assistance is just a waste of resources. To get rid of it, click Start, right-click Computer, and select Properties. Click Remote Settings. Uncheck Allow Remote Assistance connections to this computer.

Internet Printing ClientDo you ever print documents over the Internet? Neither do I. Chances are, you won't miss out on anything by disabling Vista's Internet Printing Client.

Open the "Programs and Features" control panel and click the Turn Windows features on or off link on the left; you'll get the Windows Features dialog box. Expand the Print Services section and uncheck Internet Printing Client.

Click OK at this point, and then wait several more minutes for the system to ask to reboot. Or you can move to the next page and read the next three items in this article, which also use this dialog box.

Windows Meeting SpaceI like Windows' built-in peer-to-peer collaboration program, Meeting Space, which lets you share files across a network while editing them with a remote colleague. But I don't have any use for it in my daily life, and neither do most of the people I know.

So I shut Windows Meeting Space off. You can, too. Simply uncheck Windows Meeting Space while you're in the Windows Features dialog box. If you're not in the Windows Features dialog box, see the tip on the previous page for instructions on getting to it.

Windows Ultimate ExtrasOne of the best things you can do exclusively in Vista Ultimate Edition is turn off the really pointless features that are found exclusively in Vista Ultimate Edition. I refer, of course, to Ultimate Extras, a set of downloadable add-ons available only to Ultimate users. If you didn't pay for the most expensive version of Vista, these useless add-ons aren't a concern.

If you do own Ultimate, go to Windows Update (Start, All Programs, Windows Update), click View available updates, and check out all the worthless stuff Microsoft has made available exclusively to people who paid through the nose for the most bloated version of Vista.

As of this writing, the extras include a poker game, some BitLocker and EFS enhancements that hardly anyone uses, several sound schemes, and an odd tool called Windows DreamScene that lets you waste your precious system resources by using video as your wallpaper. If PC World ever asks me to write an article on pointless ways to slow down Vista, I'll start with DreamScene.

You can turn Windows Ultimate Extras off in the Windows Features control panel by clicking Turn Windows features on or off to open the Windows Features dialog box, and then unchecking Windows Ultimate Extras.

Tablet PC StuffI own a tablet PC, and I love Vista's tablet-oriented features -- especially the Input Panel for writing with the stylus. But if you don't have a tablet, these features are useless to you.

Turning off Vista's tablet features is a two-step process: Start in the Windows Features dialog box. If you're not already there, see the tip on the previous page for instructions on getting to it. Once there, simply uncheck Tablet PC Optional Components.

You complete the job in the Services window, which you open by clicking Start, typing services, and pressing Enter. Find and double-click Tablet PC Input Services. In the "Startup type" drop-down menu, select Disabled, and then click OK.

ReadyBoostIf you're not using this much-hyped Vista feature--which supposedly speeds up Vista by caching memory to a flash drive -- it's actually slowing your system down a tiny bit. (And if you are using ReadyBoost, it's probably still a drag on your PC. For an explanation, read "ReadyBoost Flash Drives Lack Significant Boost.")

You turn off ReadyBoost in Services. If you aren't already there, click Start, type services, and press Enter. Find and double-click ReadyBoost. In the "Startup type" drop-down menu, select Disabled, and then click OK.

Search IndexingThis one is a real trade-off. Turning off Vista's indexing will slow searches to a crawl -- I'm talking minutes, not seconds. But ditching this convenient feature could very likely speed up your general PC use significantly.

In other words, turning off indexing will help your PC's performance only if you seldom search by file content, or if you use a third-party search tool such as Copernic Desktop or Google Desktop (in which case you probably have two indexing routines running at the same time, which is an even bigger waste).

If you match either of those descriptions, turn off indexing by clicking Start, typing services, and pressing Enter. Find and double-click Windows Search. In the "Startup type" drop-down menu, select Disabled, and then click OK.

Offline FilesIf you work on files stored on a server somewhere, and you can't depend on that server always being available, Vista Business and Ultimate's Offline Files feature makes your life easier by copying the files to your hard drive and keeping them synced.

Of course, that sort of thing isn't for everybody, which is probably why Microsoft didn't include Offline Files in the Home editions of Vista. But if you have Business or Ultimate and still don't need Offline Files, turn it off by clicking Start, typing services, and pressing Enter. Find and double-click Offline Files. In the "Startup type" drop-down menu, select Disabled, and then click OK.

Windows Error Reporting ServiceEvery time Windows experiences an error -- either with its own processes or with a third-party program -- it offers to report the problem to Microsoft. In theory, doing so can help the company locate problems with its OS (and heaven knows that would be a good thing). But more than likely, your report will either go unresolved or just end up in a big ol' pile of other people's reports on the same problem. Either way, you're wasting your system's precious resources on a feature that isn't doing you any good.

To disable this unhelpful service, open the Services window: Click Start, type services, and press Enter. Find and double-click Windows Error Reporting Service. In the "Startup type" drop-down menu, select Disabled, and then click OK.

UAC: Boon or Bloat?One of Windows Vista's most controversial new features is User Account Control (UAC), which attempts to protect your system from malware by forcing you to authorize certain system-altering actions by clicking through a dialog box from time to time. To some people, this feature is an unwanted annoyance that must be eliminated. Other users appreciate the added security. While I wouldn't go so far as to lump UAC in with the other wasteful features in this article, I can certainly understand why some folks would like to turn it off -- or at least minimize its intrusive behavior. For tips on taming UAC, see Scott Dunn's excellent article "Annoyance Buster: Make Vista's User Account Control Work for You."

PC World is an InfoWorld affiliate.

Red Hat has expanded its support for virtualization technologies with the acquisition of Israeli software company Qumranet, developer of the open-source KVM (kernel-based virtual machine) project, for $107 million.

KVM is an extension to the Linux kernel that allows it to be used as a "bare-metal" hypervisor, running directly on the underlying hardware and hosting guest operating systems, said Red Hat CTO Brian Stevens.

[ Keep up on the latest tech news headlines at InfoWorld News, or subscribe to the Today's Headlines newsletter. ]

Hypervisors allow several operating systems to run independently on the same processor at the same time, with the hypervisor managing resources and ensuring that they don't interfere with one another. Depending on the technology used, the operating systems may be different from one another, or different instances of the same operating system.

A closer hold on KVM will be useful for Red Hat, which announced in June that it is building an embedded hypervisor with Web-based management capabilities, Ovirt, based on the software.

"Through this acquisition, Red Hat is assuring that KVM will remain open," Stevens said Thursday, on a conference call with the press.

Red Hat also sees the acquisition as a way to maintain a lead in the market.

"VMware runs on a version of Linux, and Citrix runs on a clone of Red Hat. Both companies need to wait for Red Hat to introduce new features," Stevens said.

Until now, Red Hat has concentrated its virtualization efforts on a rival open-source hypervisor, Xen. That project is hosted by XenSource, a company acquired in 2007 by Citrix Systems.

However, Red Hat will continue to provide support for Xen to users of Red Hat Enterprise Linux 5 at least until 2014, and will continue to contribute to development of the Xen project, Stevens said.

Qumranet also develops Solid ICE, a virtual desktop infrastructure that allows enterprises to host multiple virtual Windows and Linux desktop operating systems on a server running KVM.

All Qumranet employees, including the executive team, will join Red Hat, the companies said.

"We see this as a great opportunity to extend the KVM vision. We couldn't find a better partner for KVM and Solid ICE," Qumranet CEO Benny Schnaider on the same conference call.

Sun has released a new version of xVM VirtualBox, its platform for desktop virtualization, and is also starting to offer enterprise support for the platform, the company said on Thursday.

XVM VirtualBox 2.0 comes with improved performance and platform support, adding support for 64-bit versions of Windows Vista and Red Hat Enterprise Linux.

[ Stay up to date on the latest virtualization developments with InfoWorld's Virtualization Report blog and newsletter. ]

Sun has also developed a new user interface for the Mac platform. Mac users will also get better networking performance, as will users who are running Sun's Solaris OS. It has also improved overall performance on AMD-based systems.

To get enterprises interested in the platform, Sun now offers around the clock premium support with the xVM VirtualBox Software Enterprise Subscription, which start at $30 per user per year. Additionally, customers will receive a Right-to-Use License, allowing companies to deploy VirtualBox using their own software deployment tools.

XVM VirtualBox software lets users create "virtual machines" into which they can install their operating system of choice. Developers can for example build, test and run cross-platform, multitier applications on a single laptop or desktop computer, according to Sun.

Other programs that do the same thing include VMware's Player or Fusion, Microsoft's Virtual PC and Parallels' Workstation or Desktop.

VirtualBox became part of the Sun virtualization product when the company announced it planned to acquire Germany's Innotek in February this year. The 20MB VirtualBox is currently being downloaded about 15,000 times a day, according to Sun.

The One Laptop Per Child (OLPC) association plans to launch the upcoming second generation of its low-cost XO laptop in the first quarter of 2010, according to an official from the group.

The XO-2, an update to the original XO laptop that's designed for low-cost computing for kids in developing nations, will carry two 16-by-9-inch touchscreens and eschew a keyboard. It opens like a book and can either be held vertically for reading, or horizontal for laptop computing. When used horizontally, the bottom touchscreen displays a keyboard for typing.

[ See the related stories "OLPC's dual-boot laptop due out soon" and "Amazon to sell OLPC XO laptops." And get the latest on mobile developments with InfoWorld's Mobile Report newsletter. ]

The new design is based on the fact e-books are a necessity for schools and should make reading easier.

"The e-book reader is the most popular function of the laptop," said Matt Keller, director of Europe, Middle East, and Africa at OLPC, in an interview Wednesday.

The XO-2 was announced in May, but with scant details beyond a general 2010 time frame for its rollout. The new device will improve upon the XO, which has captured the world's imagination as a way to lower the cost of putting computers in the hands of kids around the globe, thereby narrowing the gap between modern and developing nations in terms of computing expertise.

The XO currently costs around $203 or $204 to make, said Keller, while the XO-2 will likely cost around $80.

OLPC's Web site says the goal of the project is to reach a price of $75 per laptop for educational buyers.

The key technology behind the new laptop is the touchscreen, which is being developed by Mary Lou Jepsen at Pixel Qi. The company says it already has several screen manufacturers interested in building its screens.