FYI, I've encountered this situation:
1. Create a new project using the cocos2d iOS template
2. Set deployment target to 2.2.1
3. Build the game for the device (I'm using an iPhone 4s with iOS 5, havent tested other devices)
4. Project won't compile due to tons of errors in CDAudioManager.m, CDAudioManager.h, CocosDenshion.h
It builds fine if I change the deployment target to 3.0
Is this expected behavior?