www.theoldcomputer.com

Want to jailbreak your iPhone, iPod Touch or iPad, but don’t know where to start? Download our latest manual, which guides you through jailbreaking your device with RedSn0w and using Cydia. This guide will teach you everything you need to know about jailbreaking!

http://www.makeuseof.com/pages/how-to-j ... ch-or-ipad

I also recommend Sn0wBreeze v2.9.6 which I personally used on my newly acquired iPod Touch 4G
http://ih8sn0w.com/
Download at the bottom of the page and just follow the instructions on the program