First of all pls make sure that ur iTunes is set to manually manage music. Then do it as the following dteps:
1.Connect iPod to computer, go to my computer n double click iPod drive, choose "tools" --> Folder Options--> View --> select Show Hidden Files & Foldersand click OK
2.now right click iPod Control folder--> select Properties--> un-select Hidden and click OK --> select Apply Changes To This Folder, Subfolder And Files and click OK .
3.Next, click iPod Control folder and open Music , did u see folders labeled F00, F01, F02, F03
? Now Place iTunes side by side w/ this window and make sure that Music Library is displayed.
4.In iTunes select Edit --> Preferences-->Advanced, and put a check next to: Keep iTunes Music Folder Organized &Copy Files To iTunes Music Folder When Adding To Library, click OK.
5.Last step, just drag and drop all of the F folders into Music Library of itunes.
Done!
This might be a little complicated but it definitely works well, and its totally free, better than u get a
ipod transfer or sth like that. It works for both pc and mac users.