There is a growing amount of research on barefoot running. Daniel Lieberman and his crew at Harvard have been doing a lot of work comparing barefoot running to shod running and really trying to define the mechanics of barefoot running. Their work shows vastly decreased impact when running barefoot and using a forefoot strike over a heel strike. They are careful to explain that their research does not specifically indicate less injury potential in barefoot running, but it stands to reason that with less impact there would likely be less injury potential.
Click the link to head to their site. There are videos and training tips as well as a great discussion on the bio-mechanics of running if you want to nerd out.
From Lieberman's Website: