unlock it for me? I'm looking to buy either the Sharp FX or the LG Vu by at&t and use it for metro pcs. So I don't have to pay the full price, I want to buy it on craigslist. If I take whichever phone I choose to purchase to an AT&T store, would they unlock it for me even though I didn't buy the phone from an actual at&t store?

Thank you