Not long ago I had a remarkable experience: I got to visit the nursery for what might prove to be a new form of life. At Michigan State University, a group of computer scientists, biologists, and philosophers run the Digital Evolution Laboratory. There, they are developing software called Avida which allows them to create virtual worlds swarming with digital organisms. Avida's residents show a lot of the important features that scientists consider essential requirements for life. Their evolution is particularly impressive, because it parallels evolution in the wet world in all sorts of subtle ways. And because you can run through a hundred thousand generations in a matter of hours, the Avida team can carry out experiments on some of the most important aspects of evolution that biologists could previously only study by looking at the natural world.
A (philosophically) interesting outgrowth of this sort of project is the possibility that we are living in such a computer simulation.
See, for example, the "simulation argument" article at
John Barrow wrote an interesting brief article on the possibility in _New Scientist_:
Wait till this type of software becomes available to evolve the DNA used in human reproduction.