Mozilla Corp. will release the latest version of its open-source Firefox browser Tuesday afternoon, the company said.

Firefox 1.5, which has been in beta since August and has gone through three release candidates this month, will be available for free download in editions for Windows, the Mac OS X, and Linux later Tuesday from the Mozilla site.

The first major upgrade since the Nov. 9, 2004, debut of the browser, 1.5 includes a new automatic update feature, faster back and forward page viewing, drag-and-drop tab reordering, and new support for Web standards, including JavaScript 1.6 and cascading style sheets CSS2 and CSS3.

Firefox 1.5 also sports a new tool, dubbed "Clear Private Data," that lets users remove personal data such as the browser history, saved passwords, cookies, and authenticated sessions with a single click or menu pick.

The Mac OS X edition (10.2 and later) has been improved to allow easier migration from Apple Safari and Microsoft Internet Explorer.

Firefox has won over a significant number of Internet users, most of whom have deserted Microsoft's IE. According to Web metrics firms, Firefox owns between 8.6 and 11.5 percent of the global browser market.

Firefox 1.5, which in its alpha incarnation was called Deer Park (and before that, Firefox 1.1) was delayed several times during the year. At one point, Mozilla was shooting for a March 2005 release, but that schedule slipped, first as developers realized they'd bitten off more than they could chew, and then as more features were added to the browser during the summer.

Mozilla's Firefox marketing site, SpreadFirefox.com, will launch a new campaign for 1.5 that for the first time includes video clips which Web site administrators can use to promote the browser.