Seems to be a popular topic lately...
The problem is going to be the TV tuner, which will almost certainly use about a 2 second buffer/delay in order to ensure smooth playback. For watching TV, a 2 second delay is meaningless, but for a game console it's generally unacceptable.
If you don't have a monitor that has native composite/component/s-video inputs, then you should just abandon the whole idea right now, and hook the Wii to your TV. There's no other good way to do this with computer equipment.
Not sure if this is the right forum, but i sure hope so. I have an HP express card slot Analog TV Tuner. It allows you to plug up RCA jacks to it, and i want to use my laptop as a tv to play my wii. Does anyone know how to do this? I try to do it in windows media center, and media center recognizes the wii if i tell it that the wii is a satellite set top box. It gets that far, but then it needs an IR control cable for the set top box to get any further, i don't want to buy one, and even if i did, it wouldn't be able to plug into the wii anyway. I just want to know how to use my computer screen as if it were a TV. Please help