A Genetic Algorithm is a method of design using a code, and an evolution system (survival of the fittest- gene/individual/population).

If you are interested in this area - I must highly recommend Richard Dawkins Selfish Gene.

Distributed Hardware Evolution Project

OrionRobots is conducting research into this area. I will put some of my more simple examples of code on the site in the future.

Bibliography

The Selfish Gene Richard Dawkins This book comes highly recommended. This is a highly acclaimed - yet contraversial book - which any person investigating the nature of genes should read at least once.
The Blind Watchmaker (Penguin Science) Richard Dawkins Although not officially a sequel title(that goes to "The Extended Phenotype") - this actually dives right into Genetic Algorithms, and even shows some interesting geometric forms based upon the principle.
The Philosophy of Artificial Life Margaret A. Boden This book has some excellent coverage of evolutionary biology, and explores many other artificial life areas as well - such ass cost based systems. This book could well allow someone to combine GA's and BEAM principles for some truly awesome behaviour from cheap, low power bots. I refer back to this regularly during my research.