Looks like a White-Marked Tussock Moth caterpillar. Someone on facebook shot the same thing a few days ago and this was the only ID that I could find. You have a very fine image. I have a tough time getting head-to-toe in focus.
Yep that is him alright. I actually have a couple other shots that are much sharper but this one really shows his entire body off better. That flash is a handy thing for sharpness. I may have to invest in some macro lights.
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Scource: http://www.giffbeaton.com/caterpillars.htm