If you are doing 3D in WPF, this book is a vital resource: http://www.charlespetzold.com/3D/
Having tried a lot of this myself, I can tell you it's not an easy task. WPF will choke hard on the vast amount of data you try to throw at it with a depth image from the Kinect. I ended up giving up on it actually and moved in the XNA direction for this type of stuff. So if you do figure out how to get 3D WPF to behave well with Kinect data, I would love to see your solution.