So far, there are videos from John Edwards, Rudy Giuliani, Bill Richardson, John McCain, Hillary Clinton, Dennis Kucinich, Joe Bidon, Barak Obama, and Mitt Romney.
My favorite, Barak Obama, has the most views :-) I read Obama's latest book, Audacity of Hope. He's easy to understand, down to earth, sounds honest about the pressures on a politician. He doesn't give "solutions" to current problems, but he does say how he would approach a problem if he had the chance. He is very direct in his criticism of the current administration.