Anyone who is heavy user of ArcGIS and wants to explore how to create agent-based models within it should check out the new Agent-Analyst book from ESRI.
After skimming through the chapters it looks like a great resource for teachers or individuals wishing to create geographically explicit agent-based models. There are a number of step-by-step exercises which show you how one can use points, polygons and rasters to create agent-based models. Also there is a discussion on how to create agents with simple behaviors.
More information including the book, software and data can be downloaded from http://resources.arcgis.com/en/help/agent-analyst/