A while ago I started working on a plugin for Muine that syncs your library with an iPod. I worked on it a bit more lately and it seems to be coming along, so I’m trying to get people to test it. You need this and this, to start.
Right now there is no HAL integration, as I’m having an incredibly difficult time figuring out the correct way to integrate with that stuff. What it will do, however, is mount/umount your iPod assuming it is setup correctly in fstab (correct device, ‘user’ option, etc). It defaults to /media/ipod for the mount point, but that is configurable through a gconf key (/apps/muine/ipod/mount_path).
I’ve been using it for the last few days with no serious problems. I do suggest you backup your iTunesDB file before giving it a shot, though, as corrupting that is the worst thing that can happen. You can find it at /media/ipod/iPod_Control/iTunes/iTunesDB. If you encounter problems, feel free to email me.
Update: You will need muine 0.8.3 or greater to use this plugin, as previous versions lack the necessary interface.
Another Update: I’ve checked ipod-sharp and muine-ipod into arch at http://www.snorp.net/bazaar.