ourTunes is the continuation of several open source projects designed to allow you to browse and download from other people's iTunes Music Shares
Browse your iTunes Collection by Cover (OpenGL Animation)
Transfer audio back from your ipod to a computer
iVisualize is an iTunes Plug-In that plays quartz compositions as iTunes Visualizations.
iTunesFS, a FUSEOFS based file system for your Mac, which makes all your iTunesâ„¢ playlists available as folders in Finderâ„¢!