I was looking to do the same thing awhile back... i think you have a small task on your hands. From what ive read (and played with) the info you want to save/edit is held in the .DS_Store file stored on the Ipods harddrive. The file is in binary, heres a link to a site with info on how the file is structured, with the offset and size values:
http://ipodlinux.org/ITunesDB

If you search http://www.planet-source-code.com for "iTunes" you file a few examples of pulling the info from the ITunesDB.


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