Microsoft has released the final version of IE7 (Internet Explorer 7.0) for Windows XP and made it available for free download at the IE7 site.

IE7 is a significant upgrade to IE6, offering tabbed browsing, an antiphishing toolbar, a redesigned interface and a variety of security features, including increased protection against rogue ActiveX controls.

Widespread distribution of the browser won't go into full effect until November, when it will be made available as a high-priority update via Automatic Updates, and will download automatically on to millions of users' desktops.

The release comes days after the RC3 (Release Candidate 3) release of Firefox, which has a similar feature set to Internet Explorer. Although Microsoft's program is by far the dominant browser worldwide, Firefox has been slowly gaining market share at the expense of IE.

According to the most recent figures from Net Applications, in September Internet Explorer had 82.1 percent of the market, with Firefox taking 12.5 percent. A year ago, according to the firm, Internet Explorer had an 86.9 percent market share, and Firefox 7.5 percent.

IE7 includes features for IT staff to better manage the browser on user desktops. It includes enhanced support of Active Directory Group Policy, so that IT managers can deploy and centrally manage the browser on desktops. Group Policy can manage both the Windows XP and Windows Vista version of IE7, so that IT staff don't have to manage each version of the browser separately.

The Windows Vista version will be virtually the same as the Windows XP version, except that the Vista version includes a security feature called Protected Mode, which is not available in the Windows XP version.

IE7 for Windows XP is available in English and runs on Windows XP Service Pack 2, Windows XP 64bit Edition and Windows Server 2003 Service Pack 1. It will be available in other Windows-supported languages "over the coming weeks", according to Microsoft.