2. Open aptBackup and hit backup and wait for it to backup.

3. Connect your ipod touch to iTunes and let it sync and backup.

4. After this is done hit restore on iTunes and restore to 3.1.3.

5. This should take a while but once its done you should have a clean ipod touch that has no apps other than the defualt ones.

6. Connect your iPod touch to the computer again and close iTunes. Get spirit from spiritjb.com and open and click jailbreak for it to jailbreak your ipod touch.

7. Once it has jailbroken you should find  cydia on page 2.

8. Open cydia and download aptBackup (you might have to wait for cydia to download all the packages first).

9. Open aptbackup and click restore. This should take a while depending on the number of cydia stuff you had installed.

10. Once its done I recommend rebooting so as to:

(a) Make sure its untethered and
(b) Some of your cydia apps might need rebooting.

11. Done.Now you have an untethered jailbreak on 3.1.3!

Thank you for reading and please post your queries in comments below.