The Xbox Media Center (XBMC) is a media center application for Linux, Mac, and Windows that allows you to manage/watch/listen to/view your videos, music, and pictures. It has a nice interface, can be controlled from the desktop or a remote control or via its built-in web interface, and it can be extended by custom scripts. This guide shows how you can install XBMC on an Ubuntu 8.04 desktop.

http://www.howtoforge.com/installing-xbmc-on-ubuntu-8.04