Android Developer Challenge Official Pages

Android Developer Challenge official page

Want to take part in Android Developer Challenge from Google? Follow this link first to make sure you have only official information about the terms of this contest.
Also one can find there a full variety of information needed to start developing from a scratch:

Installing the SDK
Anatomy of an App
Tutorial
Development Tools

Implementing a UI
Data Storage and Retrieval
Security Model

Design Philosophy
Building Custom Components
Optional APIs
Google APIs and Services

Package Index
Class Index
Class Hierarchy
List of Permissions
Android IDL

API Demos
Note Pad

General
Common Tasks
Troubleshooting

Google Announces $10 Million Android Developer Challenge

Google's official press release about announcing the Android Developer Challenge, which will give $10 million to developers who build mobile applications for Android™, the first open, and free mobile platform. The Challenge is intended to support the developer community and innovation on the Android platform by awarding prizes ranging from $25,000 to $275,000 in cash to developers whose applications are picked.
Read more in Google Android Developer Challenge press release

Android Challenge group discussions

Discuss the Android Developer Challenge, including questions on contest details
Read more in group discussions