I just committed ipod-sharp to CVS, a library for manipulating iTunesDBs. It’s written entirely in C#. Currently you can use it to add/remove songs, and manipulate any existing playlists. There is also a cheesy little tool that lists the songs/playlists in a given iTunesDB.
I mostly wrote it to add iPod syncing to Muine. I have a patch which does this, but it needs a lot of work still. I haven’t yet totally worked out how the HAL integration will happen, for instance. For starters, I patched gnome-volume-manager to mount the appropriate partition when it sees an iPod and invoke ‘muine —ipod-sync
You can get the code from the ‘ipod-sharp’ module in gnome CVS, or here. Hopefully I’ll get the Muine patch in a useable state soon.