If you Control-click [Macintosh] or Alt-click [PC - although this is a guess because I don't have a PC] the light color dot (see Dr. Geeps Page 4 post) you get a dialog box allowing you to enter the light color numerically. It's pretty handy if you want a specific color - for example to match the colors of two lights. I believe you can also create dark grey or even black colored lights if you want to darken part of the image. Sometimes you might do this with a spotlight to help control your lighting.

Before they made me they broke the mold!
http://home.roadrunner.com/~kflach/