Here is the release from the mozilla website:
Firefox 2 Release Candidate 3 (RC 3) is a preview release of our next generation Firefox browser and is being made available for download to Web application developers, our testing community and users who want to get a sneak peek at the next version of Firefox. Please note that at this time, users should not expect all of their extensions, plugins and themes from previous versions of Firefox to work properly.The current version is 1.5...but they do have the version 2 release in "test" mode...check it out at the
mozilla website