You can capture the screen using interop and the BitBlt. This is explained
in the GDI+ FAQ.
You could extrapolate from that code to capture a 1 pixel bitmap from the
mouse's screen position and then interrogate the colour using the GetPixel
method.
--
Bob Powell [MVP]
Visual C#, System.Drawing
The Image Transition Library wraps up and LED style instrumentation is
available in the June of Well Formed for C# or VB programmers http://www.bobpowell.net/currentissue.htm