The first time you run ToggleBacklight, it saves your current Backlight level, and sets the level to the minimum.

Each time you run it afterwards, it saves the current level and switches back to the previous level.

This allows you to easily toggle between two backlight levels – set the level you want, run the app, then set the second level you want.

To install, unzip the folder, copy the folder and contents into /Applications on the iPhone, then set executable permissions on the ToggleBacklight executable file itself.

http://www.modmyifone.com/forums/showthread.php?t=123911