Beta 8 was pencilled in for a release on November 30, but some in-house problems prevented that release as they prepared to fix nagging issues with the application.
Also See: Firefox 10 download arriving tomorrow
Most of the problems centered around synchronization, and security issues, but now it would seem that they have most of the bases covered so you should see the release appear on the Mozilla website next week.
For those of you have tried previous Firefox beta, this one should be much more stable as crashes are far less significant.
Mozilla say that “based on the Fennec Beta 3 schedule, which is targeting Dec 7th as ship, we feel it’s best to align Beta 8 with that date.” They also state with their patch notes that “there is a pending change to the way Sync UI works for adding another client.”
How is Firefox 4 Beta treating you so far? You happy with it?