The Cold storage guy you mean? That's where you can catch Regirock and Registeel. Regice must be traded from another game I think. But you must defeat Pokemon League then come back there and he will be gone.
Oh and Audacious thanks for the information. But I'm doing what's best to beat the game easily and with cool pokemon. All the gym battles are going to be too easy. LOL and once they are all full powered, no ones going to stop me. And yes you are right! I just noticed I have 3 pokemon weak against Fire!