Extrusiontek, the clouds are very good looking, but a little bit too regular. Beside the things that others recommended, you could download a freeware called Bantam3D Scatter from http://www.bantam3d.com/. It creates clones of objects, varying the size and orientation, so you get something more random, and groups them as a single importable object. But more clones means a bigger file, of course. BTW, in my experience, lattices make better clouds than stones.

-- erlik