It depends on what region they key came from. Most of the keys that have been released so far are from Europe, so you'd need to activate and download it from a European account. However, you can install it and play from your North American account. Viz hooked me up with a key from Spain, so I just downloaded it from my UK account, but I'm playing it from Distantmantra (my NA account).
I've already promised Groo a key if I get one through the Gamespot giveaway.
THE GO TEAM MUSIC IS STILL IN IT!!! WOOOO!!!!
I have to go to a party tonight.... I want to stay home and play this some more. :-(