Very simple process, please note this is tethered for iPod 3g users
Make sure you have the 3.1.2 Firmware, if not use a more stable program (older programs)
------------------------------------
1. Ok first go to this link and download BlackRa1n
2. Plug in your device to your computer, and close iTunes if it opens
3. Then with your device still on, open BlackRa1n and click "Make it Ra1n"
4. Allow your device to jailbreak and reboot
5. When done rebooting, simply unlock your device, find the new BlackRa1n application and open it
6. (Must be on Wifi) Download Cydia or Rock (DO NOT INSTALL BOTH AT SAME TIME)
7. Have fun with your Jailbroken device.
------------------------------------
It is actually much more simple than i made it, i just explained everything, including the self explanatory steps
By the way as far as i know there is no jailbreak for the newest firmware (3.1.3)
ALSO NONE OF THE KMS STAFF AND ME ARE HELD RESPONSIBLE FOR SOMTHING MESSING UP WITH YOUR IPOD OR IPHONE IN THIS JAILBREAKING PROCESS WE ARE JUST TELLING YOU HOW WE DID IT!
THANKS IF THIS HELPED POST HERE