I have a new computer and I downloaded Itunes. When I go to sync it with my Ipod it tells me i'm not authorized to have them on my ipod and tell me to go authorize to sync them. I do and I get the same message.

How can I fix this?

This is the most common problem regarding with apple product. I would suggest that you should turn the automatic sync of you itunes to prevent much more problem. Auto sync will also give iphone problem specially when your iphone is being hack then by synch it will upgrade and the problem is you can't just simple downgrade it.