You might take a look at my Biology Education Software FAQ, posted to
this group every few weeks (next post will be early next week) or
available from ftp.zoology.washington.edu in the directory /pub/doc
I don't have either of the software packages mentioned by previous
posters reviewed in there, but I have a few others that you might be
interested in.
Eli Meir
Dept of Zoology, Univ of Washington
meir at zoology.washington.edu