Microbial-Community-Modeling-in-Python is a project mainly written in Python, it's free.
An agent based model of microbial communities written in python.
This procjet is in its nascent stages. You are more than welcome to contact me if you're interested in looking at, working on or using the model but don't expect a working project until the end of April 2011. This project should be considered pre-alpha until otherwise stated.