You dont get it as soon as you pre-order it. All pre-order bonuses are given when the game ships in.(sometimes they are given when you pre-order it but its usually the game demo or something that you can play before the game comes out). I've pre-ordered stuff before and always got my stuff when I came in to get my game. You'll either get the code or a code token(you have to go on a special website, type in the token, and you'll get the code). I'm thinking its not in the case since I dont think theres a way of distinguishing which have the codes for the pre-orders and which dont.
You'll probably get this card handed to you that gives you information how to redeem the code and there will be a code hidden underneath a rip off tab so no one steals it from you.
[Edited on 07.18.2009 8:10 PM PDT]