You could use the desert preset when you create the world, or figure out all the numbers and replace the grass and dirt with sand.
(i've done it before) (i only use certain ones, its not that complicated)
Private Mod Note
Rollback Post to RevisionRollBack
Whatever you do. Dont. Mess. With. The. Dragon. EVER. It feeds on skydoesminecraft fans. Well, only the ones that act like they have been taking drugs.