There's also some good links in the following thread regarding the Fibonacci series.
http://forum.portraitartist.com/show...s=&threadid=91
On one of the links I mention in that thread, you can mouse over Mona Lisa and Leonardo's Vetruvian Man and the golden rectangles in the artwork appear. Here's the link directly to that page:
http://library.thinkquest.org/27890/...=1&tqtime=1010