Looking at the included picture, it seems one could carefully use an exacto knife to trim down their iPhone's sim card to the iPad's micro sim size. You would save the cut piece for joining the two again to put in the tray and back into the iPhone. The actual chip is in the correct place. Original sim cards were the size of credit cards. The one in an iPhone is a "mini sim". The one in the iPad is a "micro sim". However... of course this doesn't mean it will work - but it's worth a try by a brave soul. Apple may have written the software to prevent this and ATT may have a way for their network to reject it. But I fully expect the dev team to tackle that in the jailbreak version. What say you??