Didn't see a legit North American 2011 Celebi event code on here yet, so I thought I'd share the one I made; along with some others.
PRESS L+R TO ACTIVATE, WALK INTO ANY POKEMART ANY TALK TO THE GREEN DELIVERYMAN.
Celebi - North America, 2011
Ash's Pikachu -North America, 2011
Mew - North America, 2010
Jirachi - North America, 2010
Yellow Forest - North America, 2010
Winner's Path - North America, 2010