The iPhone 4 unlock is ready! Remember, unlocking is different from jailbreaking. Unlocking lets you use your iPhone on other carriers. Of course, in the US the only other carrier that works with the iPhone is T-Mobile. This unlock is done by first jailbreaking the iPhone allowing applications to be installed that Apple doesn’t approve of. Then, in Cydia, you will need to add this source: repo666.ultrasn0w.com Then you can install ultrasn0w.
ultrasn0w 1.0-1 is compatible with iPhone4 on baseband 01.59 and 3G/3GS basebands 04.26.08, 05.11.07, 05.12.01 and 05.13.04.