Jukebox
Jukebox is a program that allows you to remote control a PC playing mp3's. The remote control interface is a web page, so in theory any device that can view web pages can control the jukebox.
To see the Jukebox in action, go to the demo page.
At present the server software must be Windows 2000 or XP, running Apache 2 with PHP and Winamp. It is hoped to make the server install less restrictive in the future.