OK, I found a cool program, Google Sketchup. It's basically a “CAD for Dummies”, but it has a lot of cool features. There are user created elements you can download from Google like building, cars, trees and people, there is even a “film” section with dolly track, a chapaman dolly, a triangle jib, a techno crane, and even sandbags! The best part: it's free.
Here are some sketches I came up with for a proposed set for a music video we have in the works: (the white things are hanging kino bulbs)