On my way to switching completely to Ubuntu and not using windows anymore the Ipod syncing problem was one of the biggest pains. Everytime I when I wanted to update some of my music onto my iPod I had to reboot my computer and start windows just for doing that. Because of this being so stupid I got lazy and as a result I only put new stuff on my iPod, whether it is music or vidoes etc, only every couple of weeks if not month ^^
So here is how I did it:
1.) Go to this website and download the source for libmobiledevice, the library which makes all that possible
2.) extract the tar.bz2
3.) compile the library with:
sudo make install
but before that, make sure to check out the README file because libmobiledevice requires some other librarys that you need to install first
Once successfully installed libmobiledevie, you are pretty much ready to go. I use Rhythmbox to manage my music, but I think it also works with Amarok and Banshee, I personally haven't tryed it yet though...
Here is a screenshot of Rhythmbox syncing some music to my iPod:
On the libmobiledevice.org website they have a status list of the current development state of the library. Many things work like the syncing of music and video, filesystem access, ssh/tcp tunneling and managing apps. I think those are some of the most important. Other features work, but are still buggy, so those might take a little longer before they are fully usable.
So ya, I thought that was really cool. Now I don't have to switch to windows all the time just for using that iTunes program thingy :)