Interesting article...
from a post in scientificwhims:
Testing Darwin
Digital organisms that breed thousands of times faster than common
bacteria are beginning to shed light on some of the biggest unanswered
questions of evolution
By Carl Zimmer
DISCOVER Vol. 26 No. 02 | February 2005
www.carlzimmer.com/articles/2005/articles_2005_Avida.html

Reminds me of Richard Dawkins' The Selfish Gene...