What is a screen key? It's the child of a programmable LCD, programmable RG LED, and a nice tactile switch. It's cool, that's what it is. This is another product brought to you by a member of the SparkFun forum! You must checkout the ScreenKeys homepage as well. Very nice site and great information.
The LC24.2 can be programmed to display any text or graphics on its 36x24 pixel display. The programmable backlight can illuminate the graphic display with many different colors but is limited to Red/Green combinations. With a simple microcontroller, you can change the display and backlight once the button is pressed. It's an on-the-fly configurable, multicolor, multidisplay button!