Here’s the intro cinematic for Turn10’s Forza 3, due out in a little over a month. There’s nothing here showing how the game will play, but there’s plenty here showing the variety of cars and events on offer.
There are a number of Forza 3 cars that are quite “exclusive”, in that they require you to either preorder the game, buy the Collector’s Edition or become a VIP member of the game’s community. These are those cars.