If you can do that then you don't need another video card. Simply plug the tv in and it should register as a second monitor that you can enable.
I have a Dell E520 with 3 GB running XP Media Center with a 256MB nVidia Geoforce 7300LE PCI video card and a 19 in monitor. I want to be able use the Media Center resources to output selected program data or internet graphics to my old Mitsubishi TV via one of its S-video inputs and do so while still using my monitor.
Is it possible to add a second PCI video card and run both at the same time? If not are there any other options?