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 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.

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.