How to Unlock iPhone 3G & iPhone 3GS on 3.0.1 firmware
Learn how to unlock your iPhone or iPhone 3GS on firmware version 3.0.1 using Ultrasn0w by watching this video. Unlocking your iPhone has many perks, allowing you to break free from many of the iPhone's restrictions.
Add this source to Cydia and install Ultrasn0w: repo666.ultrasn0w.com
Jailbreak your iPhone 3G/3GS on 3.0.1 if you haven't already in order to unlock your phone: