This is the code I demonstrated at Nebraska Code Camp on 3/10/2012. I have carefully preserved any bugs for your enjoyment.
This code requires ShaderBuildTask. I believe it is the one on this page http://wpf.codeplex.com/releases/view/14962
The previous release is probably more interesting if you want to see a large number of screens showing how the data moves into your program from the Kinect and out to WPF.