A very good video explaining the mechanics of barefoot running. I'd like to point out that you don't have to run barefoot to run like you're running barefoot. You can land on the forefoot with shoes on but I find it's not as comfortable as being barefoot or wearing my running sandals. My calves tend to tighten up when I run with shoes and I'm guessing it's because they're not stretching as much because the padding between my heel and the pavement is in the way.
Last week I was actually thinking about buying some shoes because mine are pretty worn. The soles are fine, but the material on the sides and covering the toes is wearing thin. Fortunately, I came to my senses. I really don't like having a padded heel so I'm going to try aqua socks next.