I'm a bit confused on unlocking my ATT iPhone 4. I have read I can call up AT&T and have them unlock (to use on StraightTalk) it since I am past the 2 year contract. I was planning on giving it to someone else, and buy a new iPhone in Sept for myself. But it says I can't be in contract (which I'm not), however I'm grandfathered in to the unlimited data plan. Would I lose that if I had them unlock the iPhone 4 before the new one comes out? And then I would be stuck when I get the new one with a worse plan. Any advice on the best way to do this is appreciated. Thanks.