Apple yesterday seeded iPhone OS 3.1 and iPhone SDK 3.1 betas to developers for testing, and users have been digging through the new releases to document new features. Among the changes found so far by readers in our forums, at Redmond Pie, and at MobileCrunch:

- Trimming video clips on the iPhone 3GS now offers the ability to save the edited version as a copy rather than simply overwriting the original file.

- Voice Control over Bluetooth is now available, allowing users to Initiate calls and control music playback via Bluetooth headsets.

- MMS is now enabled by default, but still not supported by AT&T.

- iPhone vibrates when rearranging Home screen icons.

- A "Fraud Protection" toggle is now available in Safari settings.

- iPhone startup and shutdown and app launching times have improved.

- New APIs allow developers of third-party application to access and edit videos.

- OpenGL and Quartz have seen improvements.