The code is distributed via an online subversion repository, where you can not only access the vanilla sources, but also create your own branches to share with other developers. Purchase of this product also grants you access to the Darwinia and Multiwinia development forum and wiki, where you can discuss mods with other developers.
For those specifically interested in modding Multiwinia, we are running an entirely separate Metaserver for multiplayer testing. Each copy of the Soure Code includes five authentication keys, meaning you can code changes to Multiwinia and test with 4 players and still have a key spare.
Note: You will need Windows and Visual Studio 2008 to build the games. We have tested that the code compiles correctly on the PC, but you will need to put some effort in to compile for Mac / Linux. There is no Xbox code in this release.
This continues Introversion’s long term plan to eventually release the source code to all of its games, a process started with the Uplink Dev CD several years ago. We hope to continue doing this in the future!
I’m not sure it qualifies as “releasing your source code” if you charge for access to the Subversion repository. Interesting idea, though.
We’ll keep watch for interesting projects that utilize the source, such as a Multiwinia port.