Download of ipod music to my MacBook library

if you have plugged the Windows formatted ipod into your mac and then formatted it using the mac, there will be no music left on the ipod. if you want to retain the windows format and the music currently on the ipod, you must say "no" to any offer to format the ipod that the mac itunes may prompt you with.
if you haven't formatted it, then you can use third party programs such as yamipod which allows you to copy music from ipod to your desktop which you can then import into itunes. search google for yamipod.