iPhone 4 owners wanting to unlock their combination iPod and smartphone for use on other cell service provider networks are in luck now that ultrasn0w 1.0-1 is available. The iPhone Dev Team released the hack late on Tuesday for jailbroken iPhones.
The new ultrasn0w unlock is compatible with the iPhone 3G, 3GS and 4 and is surprisingly simple to use. For U.S. iPhone 4 users, unlocking means your iPhone 4 will accept SIM cards from other carriers such as T-Mobile, although it still won’t be compatible with Verizon’s wireless network.
The ultrasn0w unlock isn’t approved or tested by Apple, so users need to be careful when upgrading to newer versions of iOS because there’s a chance that their iPhone will stop working or the hack will break.