display to a TV

Okay, this has got to stop. Every time I want to watch something on my TV instead of my monitor, I need to switch to Windows. I have no idea where to start with this, aside from the xorg.conf file, but I'm not sure of what to do with it. I have a Radeon 9600, using its S-video out with a converter to regular composite cable to a tube television. What do I need to do in order to watch videos in Mplayer on my TV???