From ModMyiFone - Wiki
This guide will teach you how to unlock an iPhone which is activated, jailbroken, and running the 1.1.1 firmware.
This tutorial assumes you already have an activated, jailbroken iPhone with 1.1.1 and Installer.app running. If you do not, you can do all those by following this simple guide. Make sure you have a SIM-card with PIN turned off (the supplied AT&T card works fine) IN the iPhone. You can use the new SIM you will be using if you are unlocking, or you can simply leave the AT&T one in there.
Step 1. - Install anySIM 1.1
Open Installer on your iPhone. Add the i.unlock.no source (see this guide for how to install it - the i.unlock.no source is simply http://i.unlock.no).
Click Install at the bottom, then scroll down to Unlocking Tools.
Click AnySIM
and then click Install.
Step 2. - Unlock the iPhone
All right, you should now have anySIM installed on your iPhone. (You may have to restart the phone for it to show up, but shouldn't have to). On the homescreen of your iPhone, click the anySIM icon. You will see this screen:
Slide to unlock like it asks.
The next page will display a TOS. Read it, scroll down, and click OK, Unlock My iPhone.
Wait a few minutes as it goes through the steps, and then you will get a success message!
Congratulations, you're running an unlocked iPhone with the 1.1.1 firmware!
