Ok guys, I'm new to the iPhone scene. I have unlocked and jailbroken iPods in the past but never an iPhone. Now I bought a used 16g iPhone 4s off ebay the other day. Just received it and I'm having trouble setting it up. It came with a Rogers sim card already in it, which was strange but regardless I found out that the phone is a Model MD234C which makes it Sim locked. Now I'm not sure exactly what that means. I'm confused whether I can set this up with a Tmobile or AT&T sim card or not. Anyone got an idea what I can do here or did I just get jacked via ebay?