Planning to get a 1st Gen. iPhone and put my SIM card into the iPhone and using it as a regular phone (No DATA plan)...IS THIS POSSIBLE? If I decide to get the DATA plan...would I be subjected to a contract? I'm planning to get a iPhone from Craigslist and I had my SLVR over two years so I'm free to upgrade or flee to another carrier. Any input will be appreciated...THANKS!!!