Apple has released yet another beta of the iPhone OS 3.1 along with a new SDK. Developers can download the latest build from the Apple Dev page. While the changes or improvements are not clear, it is said to bring video APIs for the development of augmented reality apps.
The earlier OS 3.1 builds had brought some interesting features like allowing developers to access the device over Wi-Fi instead of USB, video editing features and support for Voice Control over Bluetooth headsets.
UPDATE: WhenwillApple has posted a video showing copy/paste video feature.