I have been walking around a bit in my new Vibram FiveFinger barefoot shoes. I just went out for my first short and easy run in them.
The only thing I felt was that I am way out of shape. But I didn't feel any pain in any of the parts I was having pain in recently. Of course it was only a very short run so it might not mean anything.
I must say I did feel that I was using different muscles in my foot and leg than what previous running, with shoes, used, and I felt my legs getting tired in those areas. So it will take some time to build up those muscles.
But it was a good first attempt.