A few questions about the technique mentioned...
 
One, just wondering how the wind-driven noise is supposed to be done.  I guess my thought was to interpolate texture coordinates instead of noise values.  Is this the correct way to get clouds to actually move instead of just morph from one orientation to another?
 
Secondly, the article talks alot about using render to texture.  I implemented it in well, 10 passes (could bring this down alot with multitexturing, but im just trying to get it to look right now).  So, i have two passes for each octave, a pass for the subtraction, and a pass to make the texture the color of the sky.  Is this a bad idea?