Blackra1in is a jailbreaking and unlocking tool for iPhones(2G, 3G, 3GS) and iPods(1G, 2G) developed by GeoHot. You can jailbreak your iPhone with baseband 05.11.07 with 3.1.2 OS.

Pre requisites

1- iTunes
2- Blackra1n

.Follow this tutorial to jailbreak your iPhone or iPod.

1- Connect your iPhone or iPod to your PC.

2- Upgrade your iPhone or iPod to OS 3.1.2. (For those who dont know how to upgrade your OS, here is a small tutorial, others jump to step 3)

Download the IPSW file according to the model of your device, google it to get is easily. Launch iTunes, while holding the Shift button on your keyboard press the Restore button and selest the IPSW file you already have downloaded

iTunes will ask you to confirm it, Click on Restore and your OS will be upgraded automatically

3- Now launch Blackra1n and click on make it rain.

4- Blackra1n will enter in recovery mode.

You will see a message that your iPhone is jailbroken and wait for reboot click OK on that message box, and thats it, your iPhone or iPod is jailbroken.

Enjoy your jailbroken iPhone or iPod. Click here to learn how to unlock your iPhone.