Google have released the source code to their Android platform today, describing it as "probably the largest repository of open source code that has been released at any one time" - the code base weights in at a hefty 2.1GB before compilation.

Google's approach is in stark comparison to the closed platform approach taken by Apple for their iPhone, and comes a day before the Android phones are due to hit the market for the first time, and is the first time a fully fledged mobile operating system has been released into the developer community.

The code includes the full stack, from it's Linux-based operating system up to some key mobile applications written in Java. The applications include an email and IM client, web browser, and of course a telephony client for making calls. The google site details how to get up and running on Linux and Mac (there's no Windows support for building the OS at this time).

Developers wanting a slightly easier route to getting their head around Android still have the standard developer SDK for building applications on the Android phone.