RoboGen
I am no longer actively working on RoboGen, but was formerly the project's lead developer.
RoboGen™ is an online open source platform for the joint-evolution of robot bodies and brains. It has been designed with a primary focus on evolving complete robots that can be easily manufactured via 3D-printing and the use of a small set of low-cost, off-the-shelf electronic components.
Visit robogen.org for more info.