hey
I think there are a number of Composite to VGA boxes around for game consoles, but I read that you must be careful, as the picture quality can be quite low on some or something. It would be nice if there was a nice/cheap VGA box that supports both Composite and Component, I haven't really done much searching for one, so I dunno.
I have found mods for converting either
Component or
D-Terminal cables into VGA (hd-15), but I'm not sure if games that don't support 480p (progressive scan) would display properly.
Ohh, and I think there were a number of places which sold 3rd party VGA Cables for the GameCube, but I don't think they would work. But maybe you should lookout for something simular for the Wii.
I actually started a thread about this sorta stuff... but it didn't go far... see
About Wii + PC + Monitor + Speakers.
cya