She is Flo-Frosh favorite Colleen Quigley:
http://www.flotrack.org/page/FloAwards
And here is a sample of her modeling work:
http://forums.thefashionspot.com/f52/colleen-quigley-73372.html
She looks like Victoria Secret model Rosie Huntington Whitley.
This should put to rest "Who is the hottest female distance runner?", especially as she starts to dominate in the NCAA's in the next couple of years and more people take notice of her.