This guide with show you how to unlock iPhone 4, 3GS and 3G running iOS 4 using ultrasn0w.

iPhone Dev Team’s iPhone 4, 3G and 3GS software unlock, now with added PwnApple. Compatible with iPhone 4 baseband 01.59.00 and iPhone 3G/3GS basebands o4.26.08, 05.11.07, 05.12.01 and 05.13.04! Thanks to @sherif_hasim and @0ranav for contributing baseband crashes.

1. Sync your iDevice with iTunes to back-up all your important data including settings, apps, music, contacts and photos.

2. Jailbreak your iDevice using jailbreakme.com (read our how to here)

3. Launch “Cydia” on your iDevice.

4. Typically, the Ultrasn0w repo is included with Cydia. If not, tap the “Manage” tab located on the bottom tab bar.

5. Tap “Sources”, “Edit”, then “Add”. You’ll be prompted to add URL source. Type “http://repo666.ultrasn0w.com” and tap “Add Source”.

6. Cydia automatically refreshes and updates sources.

7. After Cydia is done refreshing sources. Tap the “Search” tab on the bottom tab bar and search for Ultrasn0w. Once Ultrasn0w appears, tap and you should see version “1.0-1″. Ultrasn0w is a software unlock for your iDevice, so you can use it with any carrier by simply inserting the SIM card.

iPhone Dev Team’s iPhone 4, 3G and 3GS software unlock, now with added PwnApple. Compatible with iPhone 4 baseband 01.59.00 and iPhone 3G/3GS basebands o4.26.08, 05.11.07, 05.12.01 and 05.13.04! Thanks to @sherif_hasim and @0ranav for contributing baseband crashes.

8. Restart your iDevice and done! Your iDevice should now be fully unlocked.

Don’t forget to check out our HOW TO section for the latest tips and tricks!

Note: We are not responsible for any damage or loss of data on your iDevice. Use at your own risk.