It is not possible to do this through itunes, but here is a way to do it:
There is an ez way to do this without any programs at all. All you have to do is this: Plug in your iPod and double click my computer. Now click "tools>folder options." In the window that appears, click the "view" tab. Now there should be an option that says "show hidden files and folders." Select that option and click ok. Now open up ur ipod directory. There should be a semi-transparent folder along with the other folders in your ipod directory (Calendar, Contacts, Images, etc.) Open this folder and then open the "Music" folder. Displayed here are a number of folders called "F30" or 31, 32, 33 and so on. In these folders are all your song files on ur iPod. If you save these folders onto your computer you will be able to save them into your itunes library. If the music file names were changed, the information displayed in itunes should still be the same for all the songs and if you had album art it still should be there. After you save your music onto your computer, i suggest that you go back to the folder options and hide the hidden folders again, because some hidden files on the computer are necessary for the computer to run and may be accedentally deleted if still visible, causing the computer to not function correctly. And that is all there is to it. There is no programs needed for this simple process.