Here is a pictorial tutorial to unlock iPhone on iOS 4.0.1 at any baseband using Ultrasn0w in Cydia. But before take further action you need to jailbreak your iPhone first, then proceed to unlock the iPhone of yours using Ultrasn0w 0.93 on any baseband at Cydia, here is the instruction you must follow:
- Head to “Cydia” from your iPhone
- Tap on “Manage” tab
- Then tap at “Sources”, see the exact position of it below:

- Tap on “Edit”, then continue tap on “Add”. Then enter the following url sources: http://repo666.ultrasn0w.comand then goes to “Add Source”

- Now wait for Cydia to updating the sources of yours automatically
- When the installation is finished. Find or search for ultrasn0w 0.93 app inside Cydia, then install the app because it will unlock your iPhone automatically to give you the ability to use it using any carrier.

- Now restart your device (iPhone) to see that your iPhone 3G on iOS 4.0.1 is unlocked now!
