you will probly do this the same way as i do with my ATI Radion 9600xt so ill explane how i do it.

Just connect another monitor to the DVI-I Output or connect your TV to the S-Video output.

Then right click on your desktop, click propoties and click the settings tab.
You should see you monitor and another grated out one, click on the grayed out one then check the box extend my windows desktop on to this monitor

and if all goes well you desktop should be extended on to your tv/monitor.

If you click advanced you can mess with it some settings like cloneing you desktop or which way it extends from (left or right)

Good luck, below is how it works out for me