The following is the typical information on unlocking show in red font (please do not try that at home, you will kill off your iPhone 4 and we will not be responsible. You have been warned not to use the information to wreck your phone!).
The Dev Team has updated their UltraSn0w iPhone unlock for iOS 4.2.1. UltraSn0w 1.2 will unlock iPhone 4 baseband 01.59.00 and iPhone 3G/3GS basebands 04.26.08, 05.11.07, 05.12.01, 05.13.04 and now 06.15.00.
If your iPhone 4 is not on baseband 01.59.00, you will not be able to unlock it. If your iPhone 3G or 3GS is on one of the baseband version mentioned above, then you can follow the instructions below…
If your iPhone 3G or 3GS is not on one of the baseband version mentioned above, you will have to first update your baseband to 06.15.00. See our Pwnage Tool Tutorial or RedSnow to do this.
This process doesn't come without its share of risks, so it is very important you read thisbefore doing anything. Seriously, make sure you read it.
Step 1: Make sure your iPhone is jailbroken using Pwnage Tool or RedSnoW
Step 2: Launch Cydia, and search for UltraSn0w.
Step 3: Reboot your iPhone.
Your iPhone is now unlocked. There is no real way to test it until you pop a different SIM card in.
He is a sly crook with extremely well-oiled tongue. He will charge you $50 or $85 (depending on how innocent you are) to "try to unlock" but will not guarantee it will work. Then he will use your iPhone 4 as a guinea pig to do the unlocking. According to sources, this dodgy crook operates from a run-down "high-tech" lot, looks like cheap a $2 dollar shop (a fat China lady is alway hanging around for what purpose, no one knows!).
Once he kills the iPhone 4, he will start to blame the world, God, his dog. Upon which, he will be driving around Auckland hunting for repair centres to save his ass (most of the time this failed as there is no known solution yet for 4.2.1 unlock on iPhone 4G).