This is a variation of the original Earthen Ibex by Rico Ambiescent (http://www.gnome-look.org/usermanager/search.php?username=rico-ambiescent) except I have re-scaled the original 1900 X 1200 picture down into 1600 X 1200 and 1280 X 1024, basically to suit my non-widescreen monitor.

This wallpaper really suits the "DarkRoom" theme included with Ubuntu 8.10 Intrepid Ibex. To use this theme right-click on desktop and select "Change Desktop Background", go to "Themes" and select "DarkRoom".