George, I can help with this. I am pretty sure that what you are talking about is from a pond management website called Inspired By Nature at:
http://www.ibnature.com. On the home page look at the lower right corner under Fish Info. The download fish calculator for the desk top is there. I use mine often. This is a virus safe and spam free site. I know the fellow well who created the "Fish Calculator". In creating the fish calculator, he used the standard weights and formulas provided in Dr Willis' Fishery Techniques book.
POSTSCRIPT - As of 2009 Inspired By Nature has removed the Fish Calculator from their website. The author of the program has given me permission to send it to Pond Boss Members. Contact me for a copy of it.
