I thought so - thank you very much! I haven't got my head fully around lifecycles, but I think that makes sense. So on my HTC Hero, if I press 'back' then the app is still there, and the local service is still connected; until Android decides it's time to be destroyed, at which point the service goes too? So local services would be used for a long-running task which should run even when the activity isn't visible, but isn't essential that it completes?
Also, the Service class seems to have two ways to work - either startService() which assumes there's some payload code in onStart() to work through and then die; or by bindService() which assumes I'll use IPC calls via my AIDL stub, and stays around until I explicitly stop it?