Attached Link: http://www.renderosity.com/viewed.ez?galleryid=150461&Start=1&Artist=sdnoble&ByArtist=Yes

I got a fairly good desert effect by "carving" a gully out of the infinate plane using a negative terain, then using just a thin layer of haze the same colour as the ground and a good chunk of near cloudless sky. That gave a grood "endless desolate sand" kinda feel. All the terains textured in world space with the same texture (kinda goes without saying eh?). A little ambience on the ground helps the "its too bright" feel of the desert. Didn't manage to get the heat haze though. Check out the image on the link attached. There's another desertish image in my gallery but it cheagts but using twilight and cliffs across the horizon.