My Fiero,2.8 SE, got caught in a freek hail storm in Tulsa.
Hail the size of baseballs. The only damage was to the panel
behind the passenger side window. It has spider cracks in it.
My question is, other than a salvage yard, where do I find a
replacement part? What has to be done to get the damaged
panel off?

You might be able to find a decent one in a salvage yard, or if you post in the Mall section, somebody here may have one.

I'd recommend Paul McKibben and get a set of his replacements.

http://www.fierosails.com/pics.html

His prices are excellent, and his service is 2nd to none.

I'll second that about Paul McKibbon. I put one of his sail panels on my 85 GT and it is an awesome product. They are identical to the original.