Dawn, Great minds think alike. As a matter of fact the first picture of this cloud that I posted is cropped exactly how you suggested. Check it out. It was posted 7/29/02 or you can just go to my images.
Hi Deborah, I think you have done well with the exposure, captured cloud detail well and the rays of light. May I suggest some cropping, quite a bit off the bottom and some off the top as well, so that about half the main cloud remain and only the ray at the top, just a thought :)
Chris, Thanks for the comment! I want to say that it was 250/F-5.6 but I took like 6 of these shots and (big mistake) I did not write them down. We were standing just south of a building in it's cast shadow at the time and that helped because it was so bright in the direct sun. I zoomed in about halfway to get all the rays I could. It was late in the afternoon and the reason this cloud is so low in the frame was to crop out the trees below.