If you don't mind doing a bit of programming, you might try my program
EcoBeaker. It's primarily meant to do individual based modeling, but
also does cellular automata, and you could program in game theory
models quite easily (it would only take probably < 50 lines of code,
most of it cookbook). Check out my web page at
http://www.webcom.com/sinauer/ecobeaker.html (the program comes with
all source code - mac only right now, but Windows in the spring).
The other place to check, which (despite my wanting to market my
software) probably has more appropriate programs, is the web site for
the Santa Fe Institute. Any of the web searchers should be able to
find it, and it has a lot of software to do anything remotely related
to the artificial life field. Again, some programming will probably be
required to do what you want.
Dept of Zoology, Univ of Washington
meir at zoology.washington.edu