So what about those situations where you are connecting your iPod to your existing iTunes library? For example if you accidentally deleted a few tracks from your main iTunes library that you want to recover from your iPod. In this case, the iTunes automatic sync will run without notification since it’s the same library database. Fortunately, iTunes offers a solution for this as well: Simply hold down the SHIFT+CTRL keys (on Windows) or CMD+OPT keys (on a Mac) while you are connecting your iPod to your computer. Keep holding these keys down until your actually see your iPod show up in the iTunes source list. This will prevent iTunes from running any kind of automatic sync when it detects the iPod, but the iPod will again remain connected and ready to work with.
got it from
http://www.ilounge.com/index.php/art...d-to-computer/
hope it works. otherwise there is software you can download that will let you take the music off your ipod.