Pick up a book such as Hello Android. It's an easy read to skim through to pick up the basics of Android. I also bought this book buy Reto Meier.
You can also learn a lot by reading some of the more popular questions on Stackoverflow tagged Android.
Poke around some open source projects. There are some popular ones such as FourSquare that you can look at. Here is a list on Wikipedia.
I also wrote about some of my first experiences on Android here with my open source app.