Please take a look at the Google API Client Library for Java which supports Android
It also supports new GData technologies like the recently announced partial response/update and JSON-C, both of which can be a dramatic improvement in efficiency on Android.
To start, please take a look at the Android Developer’s Guide. Also, please look at the Android sample for Picasa Web Albums Data API, which demonstrates the ability create/update/delete a photo album and to upload a picture.
Full disclosure: I am an owner of the google-api-java-client project.