iTunes does of course only allow you to add songs to your device, but that doesn’t mean you can’t take songs from your iPod. If for some reason you lose your music library on your computer, then you will be able to take songs off your iPod in a couple of different ways.
First off, for Windows users you simply have to access the iPod device through ‘My Computer’. Here, if should appear as a removable device. Simply explore the device as you would any other mass storage device, and find the music folders. Drag and drop them from the iPod and they’ll be saved to your computer. One problem with this, however, is that the songs will not be named correctly.
Third party software can do it a little better. PodUtil, CopyPod and iPodRip are just two pieces of software that do the job a whole lot better. All of your song names will remain intact.