I outlined how to build a Tab based interface with Swiping that included a Google MapFragment (in the form of SupportMapFragment from the Android Support library)
Turns out that there are a number of steps to get Google Maps API working for your app. The developer page here does a pretty good job of explaining how to set up the API.
Just two quick notes to augment what they said:
- keytool is in your jdk’s bin
- If you use multiple machines for development, you can use the same debug.keystore for all the machines. Preference -> Android -> Build -> Custom debug keystore