In addition, Google will award $10 million to developers whose applications are deemed "innovative and compelling" by the Open Handset Alliance (OHA), the organization in charge of overseeing the Android platform.

Last week, Google unveiled the OHA and Android, ending months of speculation over the company's plans to simplify and reduce the cost of developing mobile applications.

On Monday, with the SDK's release, Google also provided more details about Android, an open-source development platform that contains a complete set of components, including an operating system, middleware stack, user interface and applications.

Android is built on the Linux 2.6 kernel, includes a virtual machine called Dalvik to maximize application performance and will come with a core set of applications including e-mail client, SMS (Short Message Service) program, calendar, maps and a browser based on the open-source WebKit engine. The entire Android platform will be made available for free under the Apache Version 2 open-source license in 2008, according to Google.

The SDK has been designed to let developers "extend, replace and reuse" software components and comes with debugging tools, libraries, a device emulator and sample projects, Google said.

A plug-in also comes with the SDK to integrate its tools with the Eclipse open-source development platform.

To use the SDK, developers need to download it to an x86-based computer running Windows XP or Vista; Mac OS 10.4.8 or later; or Linux Ubuntu Dapper Drake or later.

Developers will also need Eclipse 3.2 or later, with Java Development Tools and the Android SDK's plugin, or Java and Javac 1.5 or 1.6; Apache Ant; an integrated development environment; and Python 2.2 or later, Google said. Meanwhile, Google will award cash prizes ranging from $25,000 to $275,000--up to a total of $10 million--to developers whose applications are picked by a panel of judges as part of the Android Developer Challenge.

Developers will be able to submit applications between Jan. 2 and March 3 of next year. The 50 best ones will receive $25,000 awards so that they can be further enhanced.

Those applications will then be eligible for 10 $275,000 awards and another 10 worth $100,000 each. Those awards will be announced in May 2008.

Another "challenge" will be launched after the first handsets built on Android become available in the second half of 2008.