David Garrett, newsfactor.com

On Tuesday, the Mozilla Foundation is expected to release the final version of Firefox 2.0, the latest iteration of the open-source browser that has been nipping steadily at the heels of Microsoft's Internet Explorer. The new Firefox version comes less than a week after Microsoft released the long-awaited version 7 of Internet Explorer.

And don't forget Opera, which, according to some, has more features and renders Web pages much more quickly than other browsers. Version 9 of Opera was released in July, in a prelude to this week's prize fight between Microsoft and Mozilla.

But if the browser battles are back in full swing, which one is winning the war?

According to analytics firm OneStat, Microsoft owns a crushing 86 percent of the global market and Firefox has just over 11 percent. Opera weighs in with less than 1 percent.

But data from companies such as Net Applications, which keeps tabs on the browser market, shows that Firefox has been adding market share for months.

And W3Schools.com, a Web site that caters to early adopters, Web designers, and other technical experts, reports that Firefox accounts for nearly a third of its traffic.

Comparing Apples to Apples

Carmi Levy, senior analyst with the Info-Tech Research Group, said that Internet Explorer 7 "puts Microsoft back into the features game."

Some of the cool new features of IE7 include tabbed browsing, built-in anti-phishing protection, a new print-preview feature that lets you fit a Web page onto a single sheet of paper, and one-click erasure of your browsing history.

Not to be outdone, the new version of Firefox has tabbed browsing, enhanced security, and the ability to auto-suggest search terms. Firefox 2.0 also maintains the features from prior versions that made it a favorite with Internet aficionados. Some of the top features include extensions, or add-on programs, that let you do everything from synchronizing bookmarks to viewing weather reports.

Opera, which has the smallest market share, might actually have the largest feature set. Like its competitors, Version 9 includes a tabbed interface. In addition, Opera also offers a transfer manager for large downloads, a customizable content blocker for keeping ads and pop-ups in check, and a "mouse gestures" feature to give the mouse a little more power.

Opera 9 also provides voice control, skins, built-in support for BitTorrent, and a kiosk mode. And, it offers integrated one-click widget downloads.

What's It Mean for You?

"Competition in the browser space is always a good thing," said Info-Tech's Levy. Microsoft let five years pass before releasing a new browser, because the company followed what the market told it to do, he said. "And in this case, the market was not telling Microsoft it needed a better browser."

But the entrance of Firefox a couple years ago changed that, Levy went on to say, forcing Redmond to up the ante in browser features and give consumers more options.

Levy also pointed out that Microsoft still has an edge in the corporate sphere. Even though other browsers cost nothing to download, he explained, the cost of fielding support calls on large-scale deployments could make Firefox, Opera, and other minor browsers too much of a hassle for corporate I.T. departments.

So now that Microsoft, Mozilla, and Opera have unleashed the dogs of war, all that remains to be seen is which browser takes the biggest bite.