WikiPedia:Prisoner's_dilemma
See also IteratedPrisonersDilemma
On http://www.spectacle.org/995/source.html I found:
"You can play the prisoner's dilemma online against a computer opponent at" http://serendip.brynmawr.edu/playground/pd.html
with some pointers to online literature, e.g.
http://william-king.www.drexel.edu/top/eco/game/game.html