Here is a summary of all the new features developers will be interested to work on the new release. And to me this really sounds interesting.
Features
1. Support for SIP-based VOIP
2. Near Field Communications
3. Support for Gyroscope
4. Multiple Camera Support
5. Mixable Audio Effects
6. Download Manager
7. StrictMode for improving Application Performance
8. New additions to the UI Framework
9. Support for large screens
10. New OpenGL methods
11. Content Providers for AlarmClock, MediaStore, Settings and ContactsContract (For SIP Contacts)
12. Improvements to Location Manager
13. Storage Manager
14. Improvements to Package Manager
15. Telephony support to CDMA EVDO Rev B network type
16. Native access to Activity lifecycle, windows
17. Changes to Dalvik Runtime
18. New manifest elements such as reverseLandscape, reversePortrait , etc.,
19. New permissions for Alarm, SIP and NFC
20. New feature constants for front camera, nfc, barometer, gyroscope, sip, jazzhand (5 point multitouch)
Those who are interested in learning more, visit the android developer site from here.