Beta version of Firefox 3.7 is on works and should be released this year. Mozilla team has already ported second Preview version Firefox 3.7 Pre-alpha build for Windows, Mac and Linux users.
Firefox 3.7 Alpha 2 user interface is not different from its Firefox 3.7 pre-Alpha 1 built; rather it has been aimed to improve speed and performance further. Being a pre alpha version, the half cooked built of Firefox 3.7 may contain some bugs and might crash your browser. If you really want to test the firefox 3.7 then head over the direct links to download firefox 3.7 Alpha 2 now!!