One of the most common chronic injuries in runners is planter fasciitis, or an inflammation of the ligament running along the sole of the foot. There is some evidence that the normally unyielding plantar fascia acts as the support for the medial longitudinal arch, and that strain on the proximal fascial attachment during foot strike leads to plantar fasciitis (Robbins and Hanna, 1987). Barefoot running may induce an adaptation that transfers the impact to the yielding musculature, thus sparing the fascia and accounting for the low incidence of plantar fasciitis in barefoot populations (Robbins and Hanna, 1987).
And here’s another story on barefoot running: http://www.wired.com/wiredscience/2009/07/barefoot/
And an entertaining video review of Vibram FiveFingers by Tim Ferriss, the author of The Four-Hour Workweek: http://www.fourhourworkweek.com/blog/2009/05/07/vibram-five-fingers-shoes/