Screensaver as your Desktop Background in Mac OS X
Wallsaver is a freeware utility that allows you to easily take a screensaver and make it your desktop background.
The application makes use of your Mac’s GPU (graphics processor) which leaves plenty of power left over to carry on with your desktop tasks. Removing the screensaver background and reverting to your previous choice of desktop decor is as simple as right clicking and selecting “restore”.
To get WallSaver to work, you will need a Quartz Extreme capable graphics card with at least 32 MB of memory and, obviously, a screensaver.

[...] BackLight looks to no longer exist, but a different app called WallSaver achieves similar [...]