Mocha is awesome. A lite copy comes packaged with After Effects CS4 and I upgraded to the Pro package when they offered it at a deep discount. It's a planar tracker and can track objects that point trackers simply can't. It looks at the whole shape that you want to track instead of just the corners and it does an outstanding job. It also handles the skew of rotation. I tracked a new sign on the front of a school bus that was passing by and the sign turned perfectly with the angle of the bus. Very convincing.

~jr