Faceshift.com is what I have played with most. It's amazingly accurate with even the current kinect, but starts at $800 for the indie version.

Brekel.com have a less expensive version, but I have no experience with it.

Open source alternatives seem thin on the ground, if not non existent.

Try faceshift, there's a free trial. It's mind blowingly awesome.

$800 for a facial mocap solution sounds, frankly, brilliant. I shall check it out on Monday/Tuesday.

How does the setup work? I'm assuming you have to spend a while tying expressions to morph targets on the model?

Takes about 5 minutes to train the model using some simple expressions. Deals with detailed facial expressions, eyelid movement and iris tracking (the eye stuff is 'OK' - this is where the newer high resolution kinect should help, if supported).