Open up Itunes in the top left hand corner select file from the drop down list select library then you will have options to back up to disc organise library export library import playlist and export playlist
open Itunes in the top left hand corner select file from the drop down list you will see Library click to open then you should see back up to disk then more options back up entire library to disk
other programs you might use to back up your Library http://download.cnet.com/sharepod/3000-2141_4-10794489.html
Back up and restore your iPod or copy music and videos to and from the device. http://download.cnet.com/podtrans/3000-18546_4-75733600.html
Transfer music to iPod or copy iPod music to your computer. Freeware
Hope this helps.