The engine is free to use. Its object oriented programming model is another reason to choose tokamak.

The official Tokamak web-site can be found at http://www.tokamakphysics.com where you can download the library and visit a user forum.
The latest version of the documentation is a Wiki at http://tokamak.xwiki.com, the original docs are located at http://www.tokamakphysics.com/documentation/. I am afraid this documentation is only useful for finding out the api calls, but in most cases you don't get a deeper understanding.
This is why tutorials are helpful.
Adam Dawes has created some tutorials which are very good. He explains how to get started with Tokamak in a DirectX environment. You can find his page at http://www.adamdawes.com
I want to add some more examples here using my Tokamak display class for OpenGL.