There have been tailored a lot of ways to get their iPhone 3g unlock. One that worked a long time was SAM. This was a method that made your device work perfectly. You could use it with whatever carriers there are available. However, the firmware is something that limits the services you get. True, the installation of a tweak that allows you to unlock is really easy, but you have to see that you meet all the requirements. If you do not meet one of them, you should never try to unlock it. You might lose info, or your phone would be ruined.