1. The first step we need to provide is turn off Nautilus which draws the current desktop and icons in Gnome:

gconftool-2 --type bool --set /apps/nautilus/preferences/show_desktop false

2. Next we need to turn up xscreensaver and its ‘glmatrix’ screensaver (nice Matrix movie like screensaver) in the root window (in the desktop):

/usr/lib/xscreensaver/glmatrix -root

3. Congratulations! That’s all :)

4. Optional: If you would like to start the animation whenever you log in, then create a file “~/.config/autostart/glmatrix.desktop” with the following content:

[Desktop Entry]
Version=1.0
Encoding=UTF-8
Name=No name
Name[en_IN]=Desktop matrix
Exec=/usr/lib/xscreensaver/glmatrix -root
X-GNOME-Autostart-enabled=true

ที่มา http://digg.com/linux_unix/Screensaver_as_a_Desktop_Wallpaper
ต้นฉบับ http://geekhacks.com/2007/09/13/screensaver-as-a-desktop-wallpaper/