Just a quick note - Firefox 3.0 Beta 5 has been released and distributed to mirror download sites.
There's no official announcement yet (I expect this to be made within the hour) but the release notes have been uploaded to the Mozilla website.
Firefox 3 Beta 5 includes more than 750 changes from the previous beta, improving stability and web compatibility, providing platform and user interface enhancements, and resulting in the fastest Firefox ever. Many of these improvements were based on community feedback from the previous beta.
The download site hasn't been updated yet but if you're creative with the download link you'll find it (here are the US English downloads for Windows, Mac and Linux).
I'll have more on this latest Firefox beta soon ...