It took a while but all 3 iPhones (iPhone 2G, 3G, and 3GS) can now be unlocked. You will either need to use PwnageTool or UltraSn0w to unlock your iPhone, depending on the model.
In order to unlock your iPhone, you will have to jailbreak it first. Click this link for more information on how to jailbreak iPhone 3.1.
Unlock iPhone 2G 3.1
So far, there is only one way to unlock the iPhone 2G running the 3.1 firmware. You have to use PwnageTool, which only works for Mac OS X. Follow this step by step tutorial to unlock your iPhone 2G with PwnageTool. A Windows version is in the works and it should be available in a few days.
Unlock iPhone 3G 3.1
You can unlock your iPhone 3G 3.1 with UltraSn0w. First, jailbreak your iPhone then:
- Launch Cydia.
- Add the following source to Cydia repo666.ultrasn0w.com (note there is a “0″ in sn0w, not an “o”).
- After installing this source in Cydia, search for “ultraSn0w”.
- Install UltraSn0w and reboot your iPhone.