I have asked this question a few times and noone has gotten very far with it. What I did was to move all the cameras to the exact same place and make sure they all have the same values for all fields. It works just fine until the cars go to the other side of the track where you cant see them. It was fun to tinker with, but we have toi find a way to make a camera lock on to an object other than a car and we'll be all set!
Or how about this. Make the camera so you can move around in the game world in 3d as the race is going on. Take a seat anywhere in the stands and be able to watch the rase as you just roll the mouse around to follow the cars. Now that would be super cool!!!!! Imagine hanging out in the pit area waiting for the cars to pit. that would be incredible.