I wear my vibrams all the time for running. You definitely cannot run like you can with normal shoes, because if you hit the ground with your heels you'll injure yourself. You have to hit with the balls of your feet and absorb the impact through the rest of your foot and your calf muscles.
I bought mine because I always got shin splints when running, and I haven't had that problem since. The only issue is that you'll probably pull you calf muscles at first, but afterwards it feels extremely natural to run with them. When I go out, I run about 3 miles with no issue.