The iPhone Dev Team released updated version of PwnageTool for Mac users and Redsn0w for both Mac and Windows users to jailbreak iPhone 3G running iPhone OS 3.0.

Here is our step-by-step guide to jailbreak iPhone 3G running iPhone OS 3.0 using Redsn0w for Windows users. We will publish one for Mac users shortly.

An important preparatory step before jailbreaking your iPhone 3G is to take a backup of your iPhone. Please refer to this post for more details.

As with any hack, please proceed with caution as jailbreaking your iPhone could void it's warranty.

Here are the step-by-step instructions on how to jailbreak your iPhone 3G in order to use the iPhone OS 3.0 using redsn0w for Windows

Step 1: Create a folder on your desktop and name it Pwnage.

Step 2: Now download redsn0w from here or here and put it inside the Pwnage folder that you just created.

Also, download the latest 3.0 firmware from the location given below and put it in the same Pwnage folder. Please use Firefox to download the firmware as IE seems to automatically extract the file (thanks carny for the tip).

iPhone OS 3.0 – iPhone1,2_3.0_7A341_Restore

Step 3: Extract the redsn0w zip file to the Pwnage folder.

Step 4: Connect your iPhone 3G to the computer and then launch iTunes.

Step 5: In the iTunes, select your iPhone from the list of devices displayed on the left. Press the shift button on your computer and then click the Restore button on iTunes.

(Restore is preferred as it won't create any wasted space on your iPhone)

Step 7: Once iTunes has finished updating your iPhone to the desired firmware, launch redsnw0w.exe from the Pwnage folder on your desktop.

Step 8: Once redsn0w launches, click the Browse button.

Step 9: Select the firmware ipsw (that you placed in the Pwnage folder on our desktop) and then click Open.

Step 10: Once the firmware has been verified, click the Next button in order to continue.

Step 11: Make sure the 'Install Cydia' check box is selected and click the Next button.

Step 12: Make sure that your iPhone is plugged into the computer, and it's switched OFF. Now click on the Next button.

Step 13: redsn0w will now guide you through the steps to get into DFU mode.

Hold down both the Home button and the Power button for 10 seconds.

Now, Release the Power button and continue holding the Home button until redsn0w detects the device.

Step 14: You will see a message that states that your iPhone is being jailbroken. Your iPhone will then reboot.

Step 15: redsn0w will begin uploading the new RAM Disk.

Once this activity is completed you will be see the message 'Done!', which means that your iPhone 3G has been jailbroken.

Step 16: Click the Finish button.

And when your iPhone finishes rebooting (approx. 5 minutes). It will be jailbroken with Cydia available on your iPhone's home screen so that you can install jailbreak apps.

Please don't forget to tell us how it goes in the comment section below and if if this guide was any help.

Update:

Based on reader comments, we wanted to clarify the following points:

• Redsn0w does not jailbreak iPhone 3GS as of now. We will let you know if Dev Team releases an updated version of Redsn0w which jailbreaks iPhone 3GS.
• Please note that this guide only jailbreaks iPhone 3G running iPhone OS 3.0, you will need to install UltraSn0w via Cydia to unlock iPhone 3G. You can checkout our step-by-step guide to unlock iPhone 3G using UltraSn0w.
• Please use Firefox to download the firmware file as IE seems to automatically extract the file (thanks carny for the tip).