The Apple Energy Saver control panel provides basic functionality for placing your processor, screen and hard disk in a low power mode after a certain amount of inactivity. This can of course save energy and extend your PowerBook battery life. But if you want a bit more control over these events, as well as get some nifty extra features, be sure to check out Sleeper.
Sleeper has five major groups of features.
The Disk Sleep feature, unlike the Apple equivalent, allows one to select specific drives to be put to sleep after a certain amount of inactivity. There are also selections to determine when drives should spin up or spin down. The Screen Saver portion of Sleeper will let you specify the length of keyboard and mouse inactivity before the screen dims, and by what percentage it should dim. You can allow mouse movement to wake up the screen, and can also define 'dim now' and 'dim never' corners for the cursor. A group of Energy Star settings let you further control the power saving of your monitor if it supports Energy Star low-power modes.