How to Unlock an iPhone 4 / 3GS / 3G with Ultrasn0w to use it on another cell carrier

The iPhone has always has one very big problem: that it is tied to AT&T. AT&T is a terrible network, and many iPhone users out there are probably dying to switch network but keep their awesome phone. Well now they can! This video will show you how to unlock you jailbroken iPhone 4, 3GS, or 3G using a program called Ultrasn0w, leaving it ready for use on any cell carrier in the country. Except Sprint, they don't have SIM cards.