In North America, you can only get the stuff through Dr. Pepper. In Europe, you can only get the stuff by paying. That said, I was in the same boat with not being able to find Dr. Pepper anywhere (Canada says f that), but I was able to get all the kits by way of a certain exploit which I won't detail here (and can't fully remember). Do a hunt around on these forums and you might find something of interest.

" In North America, you can only get the stuff through Dr. Pepper. In Europe, you can only get the stuff by paying. That said, I was in the same boat with not being able to find Dr. Pepper anywhere (Canada says f that), but I was able to get all the kits by way of a certain exploit which I won't detail here (and can't fully remember). Do a hunt around on these forums and you might find something of interest. "

Find Dr. Pepper bottles that have the EA games pictures on them. Get the codes, then go to the dr. pepper website, create an account, and enter the codes and choose the prize.

lol what is the prize in that? there is none of that promo here in Asia. :(

"Find Dr. Pepper bottles that have the EA games pictures on them. Get the codes, then go to the dr. pepper website, create an account, and enter the codes and choose the prize. "

Just wanted to get on here and say the universal codes no longer work. I went to the grocery store and a convenience store this morning and grabbed two Dr. Pepper bottles so I can get codes. They have Iron Man on them, but it said something about "every bottle wins" an "xbox live" theme or other prizes. 
 
After some digging around on the Dr. Pepper site, it looks like those bottles are not available now, but will be again in July.
 

They definately no longer work. I'm not too fussed, as they're only skins... but it's kinda lame that they added extra achievements for it.