Alright, here's how it goes:
If you have an iPod Touch, you're boned. Sorry, no two ways about it. They were designed to be a one-way device like that.
If you have an iPod SomethingElse, like a classic or a mini or a nano or a shuffle, go get Winamp (
http://winamp.com), and go pick up mliPod, a plugin for Winamp (
http://mlipod.sourceforge.net/), and install that into Winamp using the provided directions. Then pop open Winamp's Media Library, and just click and drag and copy crap out.