This video tutorial is in the Electronics category which will show you how to unlock your iPhone 3G on jailbroken firmware 3.0. By unlocking your iPhone you can use any GSM Sim carrier in your phone. For example, if you have an AT&T iPhone and you put a ROGERS Sim card from Canada, your iPhone will not accept it because it is LOCKED at AT&T. This is a software to unlock iPhones. Before you can unlock, your iPhone must be jailbroken. Open Cydia and hit manage. Then hit sources. Now select edit and then add. In the Cydia / APT url box enter repo repo666.ultrasn0w.com. After sources refresh, go to search and search for ultrasn0w and install it. Exit Cydia, reboot and you are done!