I’ve been barefoot running for a few months now.  I started completely sans shoes.  It was great, after work I ran on the cool grass in the little park up the street.  These are my feet after the run.  They’re a little dirty from the asphalt street and needed some toughening up but felt fine.  Barefoot running encourages fore-foot strikes with the ground (the front of the foot hits first), which generate less impact force than rear-foot strikes (cool paper with kinematic/kinetic analysis of barefoot running here).  The day after my first barefoot run, I found a thorn in my foot (I live in the desert with a lot of sharp things laying around) which I removed with some tweezers and alcohol.  I now pseudo-barefoot run with my Vibram FiveFingers.