http://code.google.com/android/adc.html 

Cool apps that surprise and delight mobile users, built by
developers like you, will be a huge part of the Android vision. To
support you in your efforts, Google has launched the Android Developer
Challenge, which will provide $10 million in awards -- no strings attached -- for great mobile apps built on the Android platform.

How It Works

The award money will be distributed equally between two Android Developer Challenges: