I wrote this program after finding the origional on the Internet in 1993. The orginal only calculated the mechnical parts of the bike. I added the enviremental calculations and metric/english conversion. (IE wind speed, weight and size of the rider, road graid ...)
A version of this program has been produced in PERL as a module. You can get it from CPAN. It includes a TK gui that looks like this:
Here is the orgional program I wrote.
The Cycling FAQ
Here is a tarball of the perl version