Yeah, I actually emailed Nintendo with this exact question and here's exactly what they said:
So, if your monitor has any of those inputs (composite, s-video, or component) then you can connect it that way. I was really hoping there would be a VGA or DVI port because Wii is so small and would be great for LAN parties.The specs I have for Wii indicate that it will have one multi-out port for component, composite, or S-video. If your computer monitor accepts one of these inputs, you should be able to use your computer monitor as the Wii display. Another option is to install a video capture card in your computer. However, the video capture cards often introduce delays with can negatively impact the playability of video games using that method. Most people will have the best results in using Wii with a TV display.
Nintendo of America Inc.
We discussed this topic quite a bit in this thread.
Hope that helped.