Well the monitor in generally WILL work with it, meaning it has the same connections in the back, but as far as resolutions go, I don't know if it's going to accept that. Surely there's a widescreen PC screen though? I doubt macintosh would have the worlds widescreen production in a monopoly...
There are graphics cards that natively support widescreen modes. There are also wide-screen PC laptops available that use graphics cards that support the wide format.
You can try the registry tweak, but don't come crying when you start seeing artifacts in your games and programs, waterfalls, tearing, synch issues, etc.
This would be a prime reason to contact the g-card manufacturer and ask.