I recently decided studying Android, and http://developer.android.com was a great resource. You should read the Application fundamentals doc first and User Interface documentations later.
There are some tutorials too.
I read the whole Application fundamentals, and that gave me a good idea of "how to program for Android" since it has its own architecture and environment. Get the idea of Activities, Services, Broadcast Receivers and Content Providers and try to adapt yourself to that structure. Then read about how Tasks work, and later go into UI.
As a subjective opinion, being Android so popular and growing, I don't think it's worth the effort to study Java ME or even C (I'd go for iPhone devel in any case with Objective-C). Android will probably give you more money and faster. Java FX might be interesting...
