I have now added my Team Foundation Server EventHandler to CodePlex, but don't get too exited as I am currently mid refractor. I am moving to the more reliable Message Queuing for the system, and probably moving it to a Windows Service instead of the current Website. I did actually start with web services but I found it more complicated to setup and create an install.
You can find the project under TFSEventHandler on CodePlex, but I do not have a build for public consumption yet. I have used the Microsoft Reference License (Ms-RL) as I may market it, but it will be free for a long time yet.
With that in mind, I will be doing some level of documentation for the system.
Fancy joining in then give me a shout over at the forum.