Dual Display Question

I have a question about dual displays. Like I have this internet video stream which my father wants to watch on the TV, so I'm going to hook up my computer to the TV.

I'm gonna get a new video card (my comp uses 4x AGP) with VGA out and s-video out. The VGA is going to my monitor, then the s-video will go into this converter thing I have which will send out a coxial cable to the TV.

Now my question is that if I do this, will the TV show w/e I'm doing on the monitor or will it be able to have two different things going on. So like on TV I could just have the video stream running at full screen and then I could just do w/e on the monitor. Will I need any special type of video card for this or will any work? It's because he will prob be watching the stream a lot so I don't want to have to not use the computer while he's watching it.

I've seen people do it on dual monitors, but I just want to make sure it'll work when one is a monitor and one is a TV. Also both will be coming out of the same video card. One from the VGA, the other from the s-video out.