Verified answer

It's not the iPod that's authorized with the computer. It's the iTunes account (you can actually use several accounts on a single computer). The easiest way to do this is to start over. Go to the iTunes Store and sign in. Click on your account on the right side of the top bar within the iTunes window. Enter your password and you'll see the account information. Scroll down and click the "deauthorize all computers" button. Then, on each computer that uses that account (hopefully its less than five), go to store->authorize computer and enter the account name and password.

Open iTunes-->Store(Located where File, Edit, View is at the top)--> Deauthorize Computer.

That should allow you to choose a computer to deauthorize and allow you to the authorize another computer that you want.

first of all its an ipod touch not a itouch. second of all each itunes store account is limited to 5 computers. so if you have bank cards and all that set up then delete the itunes store account and make a enw one