As I know, iPod can not directly be transfered to computer, we have to use some tool. Anad for Mac user, here recommended an iPod to Mac Transfer
# Copy video, music from iPod to Mac
iPod to Mac Transfer is the most powerful and easy to use tool that can help you to transfer the videos or music from iPod to Mac.
# Transfer iPod music, movies onto iTunes library;
iPod users can transfer iPod Songs to Mac easily. iPod to Mac Transfer utilizes iPod's internal database to display your iPod's contents instantly.
# Fully compatible with all existing iPod
Including iPod(1st, 2nd, 3rd, 4th, and 5th generation iPod), iPod Photo, iPod mini, iPod shuffle, iPod nano and iPod video.
4Media iPod to Mac Transfer is a best iPod to mac transfer software for transferring iPod files to mac. It allows iPod to mac transfer of music, videos, photos, podcast, and TV shows on your iPod/iPhone to Mac. Except this iPod to mac transfer, it also enables iPod to iTunes transfer as well as mac to iPod transfer.
http://gutensoft.com/Utilities/4Media-iPod-to-Mac-Transfer.html
Step-by-step guide: http://gutensoft.com/Guide/How-to-transfer-music-videos-photos-on-your-iPod-iPhone-to-Mac.htm
i prefer using Aniosoft iBackup to transfer comment from iPod to iTunes and PC as well. It enables you to transfer iPod's music and other content to any storage device and iTunes as well. And both the backup in the storage device can be recovered and restored with no any change and no any risk.And the data in the iTunes is quite in accord with the iPod's data including its playlists,rating and etc.
Good luck to you.