There’s plenty resources on the web, it’s a fairly mainstream discipline (at least amongst the younger generation).

Depending on your inclinations with regards to platform, I suggest you start with one of the following resources:

(1) For Mathematica (albeit very dated) I suggest _Simulating_Society_ by Gaylord & D’Andria (1998) http://www.wolfram.com/books/profile.cgi?id=3736

(2) For Python, I suggest you start with the github repository _Agent_Based_Complete_Economy_ available at https://github.com/AB-CE/abce