Just to be sure you can't implement gamecenter unless your a registered developer correct? I am asking because I am making a game and if I find that it is good enough I will put it on the app store and I want to make it with game center but didn't want to become a registered developer YET... So can I implement game center now or did I have to wait to become a developer. P.S. If I become a developer and then my year "contract" is up does my app get removed from the app store?