I remember the codename as softsled, too.

I'm still old-fashioned (not running Vista or MCE yet).  However, I remember reading a long time ago a fairly clever idea to stream television to a PDA (though the technique might also work in your situation).

Download and run the free Windows Media Encoder (http://www.microsoft.com/windows/windowsmedia/forpros/encoder/default.mspx).  Select your TV tuner card, quality settings, and stream it on an available port.

On the other machine, simply connect to the IP address and port number of the first machine, and you can watch streaming video.  It's surprisingly easy.

I am not sure if this will work in Vista, so my apologies if it does not.  It works fine for me in XP SP2.

This does not handle your issue with changing channels, unfortunately, but at least it can handle the streaming part.

Hope this helps.