I’ve been meaning to write this bit of software for a while now, its a simple app that dumps out all your playlists in iTunes into .m3u playlist files.
I use it to generate playlists that my HTPC (running Boxee) can play.
It’s a .NET app. You can download it here: PlaylistDumper_v101.zip
If the “dump folder” is the root of your music library then the .m3u file will contain relative paths which is useful for playing across network shares.