From the replay, it looks like Hildebrand just took the turn to fast to keep control of the car. A more experienced driver would have backed it down just a little bit, but I can imagine all the excitement probably overcame him, and he couldn't help himself. As soon as he hit the wall, JR apologized to his crew, "I'm sorry, I'm so sorry."
Hildebrand managed to hang on to 2nd place, his two right wheels hanging off the side of the car. This was an awesome ride by JR Hildebrand, and it was a foregone conclusion that he was going to win the race until that one slight miscalculation ended it. JR drove a great race and had an exciting finish, but it's Dan Wheldon's face that will grace the Borg Warner trophy for the 100th running of the Indianapolis 500.
Somebody better give this guy a job, otherwise every team who passed on him is going to like like a complete idiot. Maybe this will help Bryan Herta's team get some more sponsorship to ride a few more races and capitalize on this amazing, exciting victory.