Its almost been a week and Best Buy still hasn't emailed me the code. After the initial 48 hours was up I called in and they said they'd send it to me within another 48 hours....and now that is up. Anyone else still having this problem?
I actually got my code after contacting their gaming division on their forums.
Read the instructions, make a forum account and contact the user specified in the instructions. Be prepared to have your reciept/proof of purchase ready and be sure to remember what email address you used for the preorder (if you have a reward zone/gamer zone account & used that, use the email associated with those)
If you didn't give them an email or have one/both of the rewards accounts while preordering then that is where the problem lies.
If you did, give that link a go and good luck. I know it worked for me.
Edit Note: Keep in mind that it may not be right away. it took about a day for me to hear back and another to recieve the code. But in the end, I recieved it.