LightMe is a small preferences panes and background daemon that allows you to change brightness and power of your monitor with customizable keyboard shortcut. Using Lightme you will can reduce to a preset value the brightness, restore it to the last value (and with anther click of your restore shortcut you can switch to the max value) and poweroff the monitor.
Lightme core is a little lightweight background daemon compatible both with Intel and PPC processor. You can install it at login, activate or deactivate it with a simple click from preferences pane.
Requirements:
OS X 10.5 or later
Version for OS X 10.3.9/10.4.x available
here
Universal Binary
Author's Site
MajorGeeks TX
Internode