I bought my iPod touch for around 400$ during the Christmas of 08-09. It was only running Apples OS firmware 2.2.1 then, now it runs a stunningly fast and efficient 4.0 on the device. I got my iPod Touch for one reason, and one alone. That was the reason to hack, crack, and jailbreak the batteries out of the thing. Now with 4.0′s official release there is still a way to jailbreak your iPod Touch.
Head over to the Dev Teams post on the topic and download redsn0w. Now make sure you connect your iPod to your computer via the cable. If iTunes doesn’t automatically pop up make sure you open it, also make sure you’ve updated to version 9.2+. Now click on your device and select update. Continue through the process till your iPod’s running the non-jailbroken 4.0.
Now you need to find the .ipsw file that iTunes downloaded and updated your iPod with. You can find it at the following location on a windows 7 computer.
“C:UsersYOUR USER NAME HEREAppDataRoamingApple ComputeriTunesiPod Software Updates”
Now right click and copy the file from inside this folder, it should be named “iPod2,1_4.0_8A293_Restore.ipsw”. Paste the new file onto your desktop(or where you downloaded redsn0w to). Now execute the redsn0w jailbreak and make sure you leave your device connected. Follow all instructions on the screen.
Enjoy your new 4.0 jailbroken iPod Touch!
[ Disclamer: I am not responsible nor required to help you if you or the program messes your iPod Touch or any other device up. Enjoy and be carefull.]
Update #1: They dev-team have released beta 4 of the jailbreak, if you jailbroke your iPod Touch with beta 3 or before, you might want to consider this update because it fixes some important bugs, especialy with the new iBooks application Apple just released. The download links have been updated so get over there and be sure when jailbreaking, if your device is already jailbroken make sure to uncheck the install cydia checkbox. You do not want to install it twice. Enjoy!
Update #2: Beta 5 of the jailbreak has been released!