Check out a resource offering discussions and documentations on this subject, as well as the ability for artificial agents to evolve cooperation.

Serge Helfrich provides various suggested articles on the topic, tutorials, and a demonstration applet.

Read a detailed description and historical significance for the artificial life experiments called The Prisoner's Dilemma.

Find Java applets and article discussing the evolution of cooperation generally studied through programs supporting the Prisoner's Dilemma.