go to your ipod and on the last page there is an app titled loader. open tht and download cydia.
This is my first instructable on how to jailbreak an ipod touch with firmware 4.2.1 or lower. Jailbreaking you ipod gives you many opportunities for free stuff like music and videos, you have a theme on your ipod and so much more. A lot of people may think it takes a genius to jailbreak an ipod touch but I'm 15 and i have jailbroken 4 out of 4 i have tried to. also it is an un-tethered jailbreak and it doesnt work for 2nd gen ipod touches that are mc models. you can find out the model the same place the firmware is.
Step 1: Check your firmware
check your firmware to make sure it is 4.2.1 or lower. go to setting then general and it is under version.