The SDK documentation would be the best place for information. If you have an application idea it should be simple enough to work out, then use the documentation to find what you need to make it work.
Should get an Android device, the iPhone EULA will start adding the clause that you need to wear jeans and turtleneck top when using it. Unless you're comfortable with the stupid shit Apple comes up with (refer to 3.3.1 of iPhone OS 4 SDK :)).