I currently have my Xbox hooked up to a Samsung 930B(19 inch lcd). You just need a VGA hookup like this http://www.x2vga.com/
Only issue I have is games that are in 720p are widescreen. So the monitor stretches the image vertically to fill the screen.
Have you tried adjusting the screen size settings in the Dashboard? (I'm sure you have, just thought I'd suggest it if not)