Firefox 2 Beta 1 is a developer preview release of our next generation Firefox browser and it is being made available for testing purposes only. Firefox 2 Beta 1 is intended for web application developers and our testing community. Current users of Mozilla Firefox 1.x should not use Firefox 2 Beta 1 and expect all of their extensions and plugins to work properly.

Download: Mozilla Firefox 2.0 Beta 1
View: Change Log
View: Mozilla Firefox Homepage
Source: MSFN