Apparently March is Web browser season.Firefox4

On Monday, Microsoft unveiled Internet Explorer 9, the latest update of its browser, and trumpeted its 2.3 million downloads in the first 24 hours of availability. Earlier this month, Google unveiled the newest version of its browser, Chrome 10.

Now it’s Mozilla’s turn. More than a year in the making, Firefox 4 will be make its debut on Tuesday, bringing faster performance and a handful of new features.

And in a few weeks, the folks at Mozilla say they will release the first full-fledged version of Firefox for smartphones based on Google’s Android operating system (don’t expect an iPhone version of Firefox anytime soon, as Mozilla executives say that Apple’s terms of service prohibit third-party apps that boast standalone browser engines).

The flurry of new releases comes as competition in the browser market heats up. While Microsoft remains the dominant browser maker, the market share of Internet Explorer has slipped from roughly 68 percent two years ago, to 57 percent in February, with much of the gains going to new entrant Google, according to data on the Net Applications website.

Firefox is the No.2 player with roughly 22 percent share.

The new version of Firefox delivers a performance improvement that will make it six times faster than its predecessors, Firefox 3.6, according to Mozilla.