McLeish said that as companies think about migrating those older applications and their mandated browser from IE6, they might choose a competitive browser instead of upgrading to a newer version of IE. "I think we're going to see more and more people on IE6 figure out where they go and if an alternative can match [their needs]," she said.

Mozilla in particular is being aggressive with these companies, McLeish said.

In an interview this week, Mike Beltzner, a director of Firefox at Mozilla, said that along with the release of Firefox 3.5, due at the end of the month, Mozilla will offer tools for Web developers who want to recreate corporate applications using standards common to the modern Web -- standards that Microsoft only began supporting in earnest with IE7.

However, Mozilla still does not offer group policy for Firefox, analysts said. It also does not offer installation software to help administrators put Firefox on multiple desktops at the same time, though a forthcoming customization program planned for Firefox 3.5 will include that feature, Beltzner said.

Through the program, called Build Your Own Browser, companies will be able to use a Web application provided by Mozilla to specify certain browser customizations -- such as bookmarks to corporate intranets or portals. Companies will also be able to add their brands to the browser through technology called Personas, which allows them to create a "skin" with their logo.