The new Premiere Pro CC SDK is now publicly posted to the DevNet site here: http://www.adobe.com/devnet/premiere.html
Some highlights:
- New GPU Extensions for Effects and Transitions
- New SDK_ProcAmp sample to demonstrate GPU acceleration of an After Effects-style effect
- Closed Captioning support in Importer and Exporter APIs
- Support for new Edit to Tape panel
- XCode projects are now built for XCode 4.5
Refer to the What's New documentation for a complete list of changes.
Enjoy!