http://faqs.ign.com/articles/392/392700p1.html
2) Q: What's the point of the cheese?
A: Nothing. Rare was going to make the cheese special where if you collected a certain amount of cheese, secrets would be unlocked.
3) Q: But why did they take it out and leave the cheese in the game?
A: Time contraints, presumably.
4) Q: Is there face-mapping?
A: Nope. Rare removed it from the final version of the game.
5) Q: What happens if I DO get all of the cheese?
A: Nothing. Be proud of yourself or something.