The iPod is just slightly harder to talk to then a normal firewire hard drive. Aparently it just hides the music away in a hidden folder, while the rest of the drive is seen as normal. The challenge has been the HFS+ format they use to be Mac friendly, but a little bit more work by the linux community should result in a way to just mount the ipod, and copy music and data over. Can't get much more open then that.

I've been looking into this as well, and while folks have manually placed MP3 files in that hidden directory, it must be included in a playlist in order for the iPod to see it. Their playlists are in a proprietary binary format, which has not yet been reverse engineered completely. In addition, HFS+ has been around for ages (5+ years?) and no one seems to have gotten anywhere with support for it yet. I don't know if that due to lack of trying or lack of success, but it doesn't bode well. Despite all of this, I still plan to buy one, in the hopes that someone will eventually get it working. In the meantime, I can use my iBook to sync it.