Apple's latest "masterpiece" has been unlocked by clever hackers. (RedmondPie) MuscleNerd and PlanetBeing (two members of the infamous iPhone Dev Team) have figured out how to unlock the iPhone 4 running iOS4. Carrier unlock for AT&T versions of the new smartphone required a rewrite of ultrasn0w due to the baseband OS. This has delayed the unlocking process quite a bit.
Images and video of the unlocked phone have been posted, including one screenshot of the phone with Cydia running. Expect to see these jailbreak and unlock tools become widely available once the new iOS4 update goes through.