It seems the DVD-playing PCI cards have passed on. You would need a video card compaitble with Apple's DVD player, that has a composite or s-video output that you can send to your TV. Of course this is built-in to powerbooks and does work.
But take my word for it, it is not worth the trouble, cost, and time to do this. Just go and get a $99 DVD player and you will be much happier. Why do you think Apple stopped putting DVD-ROMs in their desktops?