This guide will help you unlock your iPhone 3G with the latest iPhone OS 3.1 firmware using ultrasn0w. This unlocking guide applies to iPhone 3G only. iPhone 3GS 
users will have to wait for the new version of ultrasn0w in order to unlock their device. iPhone 2G users can simply follow the guide I posted here to jailbreak and unlock with firmware 3.1.
Step 1: Download the latest version of iTunes.
Step 2: Launch iTunes. Make a backup of your phone’s data by right clicking on your iPhone name in the left-hand side sidebar and then click on backup.
Step 3: Now follow the guide here to jailbreak your iPhone 2G or 3G using PwnageTool on firmware 3.1.
Step 4: Once you are done with the jailbreak, you can now unlock your iPhone running jailbroken firmware 3.1 by using ultrasn0w 0.9. To do this:
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Start “Cydia” on your iPhone.
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Touch on “Manage” tab on the bottom.
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Now touch on “Sources” as seen in the screenshot below:
- Touch on “Edit” and then on “Add”. You will be prompted to enter a url source as seen in the screenshot below. Type “http://repo666.ultrasn0w.com” and touch on “Add Source”.
- Cydia will now automatically update your sources by following a series of automated steps.
- After installation is completed. Search for “ultrasn0w” in Cydia and install this application (T-Mobile users should disable 3G before installing ultrasn0w). This app will automatically unlock your iPhone so that you can use it with any carrier.
Step 5: Now simply restart your iPhone. Voila! You are now running a fully unlocked and jailbroken iPhone firmware 3.1 on your iPhone 3G.
You can follow me on twitter or join our facebook fanpage to keep yourself updated on all the latest jailbreaking and unlocking releases.
Feel free to ask me any questions here should you run into any problems when unlocking your iPhone.
UPDATE 1 (From Dev-Team): Unlocked users on the 3G will probably notice that the name and/or logo of their carrier is missing, but they still have full bars and a signal. So far this seems to be purely a cosmetic issue and it doesn’t impact your signal or coverage. We hope to have this issue “fixed” when we release the 3GS compatible version of PwnageTool.
UPDATE 2: Those of you who have upgraded to the original firmware 3.1 from iTunes should first downgrade your baseband from 05.11.07 to 04.26.08 before trying the unlocking guide posted above. Complete step-by-step guide on how to downgrade your baseband can be found here.
UPDATE 3: iPhone 3GS can now be jailbreaked and unlocked running on firmware 3.1. Follow the step-by-step guide posted here to jailbreak and here to unlock iPhone 3GS on firmware 3.1.
