Left 4 Dead 2 Demo Question

I just preordered Left 4 Dead 2 today from Gamestop and have not yet received an email or any sort of notification on my xbox about the demo. It has been about 3 hours and I'm not sure if i have to do someting in order to get the code. Any help would be appreciated

Going to have to go to the store you pre ordered at and pick up the code.

Thanks guys for the help