I'm using my ipad 3G sim in my iphone to create a data-only phone. Using skype and textfree, you can basically get rid of your iPhone ATT plan, saving lots of money. Now, I want to sell my iPad 3G. Can I still keep my SIM and pay for the data plan every month? What happens when the guy who buys my IPad gets his own sim and data plan -- am i screwed?