As said above it is really very simple to add music files on i-pod.You can go to file and import all your music files from your music folder.
One tricky part is that each i-pod is recognized by your original i-tune on pc where you first installed it.
So as kingkong said if you connect it to some other pc you will delete all data.
I tried to get around of it while this year on holidays cos i visited my sister and added thousand of pictures on i-pod of kids etc and couldn't do nothing with them except watch them and show them to her on i-pod.
I did exported it to her pc but when tried to open with other i-tune was not going to risk to lose all when message that you can lose all data appear on screen.;(
u can copy all your disks too easily, just insert it in cd or dvd and copy to i-tune library.
good luck