I finally got my hands on PS CS3, which is really exciting.
I've got a quick question now. I'm on the "Elevation Base" portion of the tutorial, and I cannot seem to get my elevations to look as natural, smooth, and high as yours do. Mine keep either looking funky and low (smaller brush with lower opacity) or getting too big and then flattening out (big brush with higher opacity). For some reason I cannot find a happy medium to make them look as nice as the elevation bases that you have in the tut image.
I tried running the clouds and difference clouds filters to see what those came up with, but they just looked weird. I can't seem to get natural looking elevations.