Monitorian - Monitorian is a Windows desktop tool to adjust the brightness of multiple monitors with ease.
Shades - Shades is a FREE utility for controlling the brightness of your screen.
Twinkle Tray - Easily manage the brightness of your monitors in Windows from the system tray.
Simple Screen Shade - Description and screenshots of Simple Screen Shade.
PangoBright - Screen dimming software that allows you to control the brightness of your laptop screens as well as external monitors.
myPoint Shade - Stop burning your eyes! myPoint Shade is caring for your eyes' comfort.