Obsidian is a web frontend for your amarok music collection.
As long as Amarok stores your collection in a MySQL database, download this plugin, put it in your htdocs folder and edit the config file with your database details.
You get a pretty page with your music collection neatly arranged. Click to add songs to your playlist, and hit 'play playlist' to stream the music straight to a remote computer!
Obsidian made me (finally) get a dyndns account. Just when you think Amarok...