easy.
first, disable auto-syncing in itunes (its under options, go find it yourself).
after you connect your ipod, in my computer, right click on your ipod and click on explore.
enable auto folders, so you can see hidden files.
in your ipod there should be a folder called iPod_Control. enter that folder, then theres a folder called Music. this is where all your music are stored in your ipod.
the files are all there, but are in random names so it will be troublesome to organise them. i recommend that you copy and paste the songs to your hard drive, then add all files to your itunes. after that use your itunes auto organise function to organise all your music files, so all your files will automatically be re-named.
alternatively, just google a programme called SharePod.
(the above method is just in case you dont have internet connection on the other com)