Early word from TiPb commenters and the Twitter show some new iPhone 3.1 features found already:
- Non-destructive video editing means trimming a clip no longer saves over the original video but gives you the option to "Save as copy..."
- Voice Control now works over Bluetooth
- iPhone vibrates when moving icons
- Updated AT&T profile to 4.2
- Updated modem firmware to 5.08.01
Behind the scenes changes abound as well:
- Improvements to OpenGL and Quartz.
- APIs to allow third party apps to access videos and edit them.
Update: Yes, MMS buttons appear to be back for AT&T users, but as with early iphone 3.0 Betas, they're non-functional on standard devices. Whether they survive to the official release this time (they were removed in late 3.0 Betas), who knows?