I would like to add Push messaging to my Phonegap Android App and believe that C2DM is the waybest way to make this work - could point me in the right direction to set this
Yes, C2DM is the Android Push solution. On https://github.com/awysocki/C2DM-PhoneGap you can find an example implementation.
The files in the com.google namespace have to be included unchanged, they are from the session "Google IO Session Overview: Android + App Engine: A Developer’s Dream Combination", see http://bradabrams.com/2011/05/google-io-session-overview-android-app-engine-a-developers-dream-combination/
So these are the steps you should perform:
C2DMReceiver (naming convention) which inherits from C2DMBaseReceiver and implement the necessary abstract eventsThe AndroidManifest looks like
If you receive on the emulator the error "E/CSE Notifications(401): Registration error ACCOUNT_MISSING", you have to add a Google account to your emulator.
For your second question: it depends what you want to do. When you receive the message and you just want to display a notification so that the user is able to start your app then you don't need a Phonegap plugin. In that case you can solve everything in java.