A web-oriented artificial-life site: Alife, genetic-algorithm and cellular-automata experiments written in cross-platform web languages (Java, tcl/tk), with free source code.
A collection of small tools for Chaos Modelling, based on ideas of Life game, Tierra and others.
http://sourceforge.net/projects/chaco/
Darwinbots - A free artificial life program running under Windows. Similar to C-Robots with a biological bent, where the robots mutate and evolve over time.
An aquarium simulation written in Java. The program uses neural networks for all of the fish being simulated, and the fish are artificially evolved from random starting information.