I'm in Korea and brought an iphone from the US. I got it at game stop, and it was an ATT phone. I have watched some videos and I think, I jailbroke it, but I'm not sure if it is unlocked. In "The apple guy video" I got to the point where he put in the new sim,but when I did the same thing mine did not auto recognize it. It said invalid sim. I can't make or receive calls which makes me think it is not unlocked. I would appreciate any help you can give. Other information I'm using SK as my provider in Korea.