Hey guys!
This might work over 4.0 but i'm not 100% sure.
It is the most simplest jailbreak ever!!!
Go to jailbreakme . com on you'r iPod/iPhone and let it download the software needed such as Cydia and the jailbreak.
It will take about 5 to 10 minutes if you have slow internet.
Screen Shots!
If you have any trouble please ask by sending me a PM or VM.
Hope this works for you as it did for me and have fun!