Phone 3.0 OS Beta 4 has just been seeded to developers for use. Like always, there are no mentions of any changes. A Pre-Release of iTunes 8.2 has also been pushed out, and is required to activate your Beta 4 device.
One interesting fact in the new iTunes 8.2 are references to Blu-Ray data from Gracenote, suggesting that iTunes could support the reading/recognizing of Blu-Ray discs.