Surprised nobody mentioned this one - better than Anapod, use YamiPod:
http://www.yamipod.com/main/modules/home/
It is free, doesn't require an install on the host machine, and allows drag and drop to your iPod.
Even cooler, plug in your iPod and drag the small (single file) executable onto your iPod. Then, any machine that you plug in your iPod and see it as a drive letter, you can run YamiPod right off your iPod and move music around.
It's free too! Works really well, and I never use iTunes now to manage my music on my 'pod.