http://www.infobarrel.com/How_To_Backup_Your_iTunes_Library
published July 4, 2008
How To Backup Your iTunes Library
by rizzle
Conveniently, iTunes 7 now offers a super easy way to back up your entire iTunes library. This includes your songs, videos, playlists and anything you've purchased from the iTunes store. In order to backup your media you are going to need some blank CDs or DVDs. The number of blank discs you will need is totally dependant on how much media you have!
In order to do this, first verify you are using iTunes version 7 or newer.
Next, open iTunes and in the file menu, select the 'Back up to Disc.'
You will then be prompted to select one of two options, 'Back up entire iTunes library and playlists' or 'Back up only iTunes Store purchases'. If you want to back everything up, select the first option, if you want to only backup what you've purchased select the second option. There is also a check box available if you have backed up your data in the past and only want to back up files since your last backup.
Finally, insert your blank DVD or CD into your drive and iTunes will begin to back all your media up! If all your media doesn't fit on one disc, iTunes will prompt you to insert another when the first disc is full. Your backed up discs will not be playable in a DVD player or CD player; you will need to restore the backup in iTunes in order to use the files.