Has been pushed to an open source project using Mercurial source control: http://code.google.com/p/eosai/
The AI has been split off into a separate dll. The code is there for educational purposes (if you want to see how an AI works), for the possibility of having a modifiable version of the AI for EOS, and for potential use in third-party games.
Splitting the code out of the executable caused some things to break, so it's not fully functional right now. The current version of EOS.exe does not use the dll, which means you can't currently modify the AI and get it working inside your EOS game.
You should be able to download the code, but not be able to upload changes to the repository. If you can upload changes, let me know. If the code won't compile, it means I missed something. Again, let me know.
And let me know if there's much interest in this and I'll devote more attention to it (including getting it working with EOS).