Stu Maschwitz, author of DV Rebel's Guide, turned me on to a free tool for creating storyboards, without sketching your brains out. It's called Sketchup, an architectural tool offered by Google. There is a pro version that has a lot of bells and whistles, but the free version (along with a downloadable library of models) is perfectly capable of generating detailed panels, and can even offer a sketch-like style to the images if you wish.
Give it a try.
P.S. I plan to review DV Rebel's Guide when I'm finished reading it. Stay tuned.