OpenKinect's knowledge base has all the theory/experiments/explanations , that are constantly added/updated.
Tech-tree has kept a really sharp track of Kinect developments.
KinectHacks maintains good updates on very interesting Kinect hacks.
This tech-tree page also talks about a very impressive use of Kinect for creating 3D road-maps of cities.
And here are Kinect Tutorials provided by ROS!! Note : it has calibrating the kinect camera
http://www.freenect.com/?page=5 also has good info.
Following are really really really important and MUST_GO_THROUGH web resources....
0) Nicolas Burrus's Post on Kinect calibration ( both color and depth )
1) The RGB Demo software ( opensource code )
- it has source code downloadable
- it has documentation
2) A small post for give links on Kinect Calibration