Google has released a software development kit (SDK) for its Android open handset project.

The SDK will allow developers to create applications to work with Google's mobile operating system.

The applications will then be able to run on any handset produced by members of the Open Handset Alliance, a group of software and handset manufacturers formed around the Android platform.

The first Android-based handsets are expected by the second half of 2008.

A set of online documentation for developers will accompany the SDK, and a new blog has been launched by the Android development team.

Google is conducting a $10m programming contest for Android in an effort to generate interest in the platform.

Developers will be challenged to create new software for the platform, and the top 50 entries will receive funding for additional development.

The contest will open in January and Google will accept entries until 3 March. Each of the top 50 applications will be awarded $25,000. Ten winners will be selected for a $275,000 top prize and 10 more will receive $100,000.

Google also is planning a second Android development contest for the second half of 2008.