oh man I cant believe I've missed this thread untill now...
I've been living barefoot as much as possible for the past year, its awesome.
I do run barefoot, I've had some trouble adapting to the ball-heal-ball pattern, but its getting better.
as for someone above saying the human body wasnt made to run on hard manmade surfaces, are you saying that any of the surfaces in a city are any harder then granite stone, or a hard pounded dirt trail? I've been running on cement and asphalt, and dirt paths off and on without trouble, just have to make sure your landing on the ball of your foot first and have your knees bent enough. If your landing ball heal ball and have your knees bent slightly the impact is absorbed by the arch and the flex of your knees as your body is designed. When you land heal first usually your knees are locked, or close to it. this transfers the impact through the cartilidge in your joints and up your legs to your back and all the way to your head.
http://www.runningbarefoot.org/ is a really awesome resource, talks about form and everything else related to this topic.
I've been thinking about making a pair of Huaraches like this guy sells kits for
http://barefootted.com/shop/