AIR3.3 IOS:When the device's screen is black, the sound is still playing.

It might be.  Could you please open a new bug report on this over at bugbase.adobe.com?  Please include any sample code or application if possible.  If you'd like to keep your code private, feel free to email it to me directly at ccampbel@adobe.com.  Finally, please post back with the URL so that others affected can add their comments and votes.

I'll give the iOS team a heads up.

Chris