Here's good news for iPhone 4 users who've been waiting for a carrier unlock. The iPhone Dev Team has released an update to Ultrasn0w, its iPhone unlocking client, that's compatible with the iPhone 4. When run on an jailbroken iPhone 4, Ultrasn0w will allow you to use a carrier other than AT&T in the US.
It's a very simple process, as the video above demonstrates. Just note that