iPod Classic 120 GB, Ubuntu Karmic, 2.0.1 firmware works

For what it’s worth, even with the 2.0.1 firmware upgrade that (as of this writing) iTunes will insist on putting on your iPod if you restore it from a Windows box, you can get it working on Ubuntu Karmic.  The trick is the program ipod-read-sysinfo-extended, which you execute after attaching (and initializing) your iPod with the drive id and the mount point, for instance, ipod-read-sysinfo-extended /dev/sde /media/IPOD.  This writes an XML files to your iPod.

You may need to run the program with root privileges