Another program that's available for PCs is The Chemical Reaction Network
Toolbox, by Martin Feinberg. The primary aim of this software is to
address the possibility of multiple steady states in mass action systems,
but it is also usable in a simulation mode. If you send an e-mail to
Dr. Feinberg (feinberg at che.rochester.edu) he should be more than happy to
send you a copy.
Paul
schlosser at beta.ciit.org