Good Software For Generating Cloud Maps?

I''m looking for a good program to make atmosphere cloud maps for planets. I found a few good actual ones for the earth but white clouds don''t work well with the other planets of the solar system I spent about 3 hours looking for maps on google w/o too much luck so I''m guessing it''d be easier to just generate some w/ perlin noise or something. Does anyone know of any good programs for doing this (preferably free )? Thanks a lot, -Ben | particlefield.com |