Free Thoughts is an excellent podcast offered by the other great website dedicated to explaining libertarianism, Libertarianism.org. Michael Munger is an economist from Duke and a great messenger for liberty.
Michael Munger, explains the benefits, and in fact the necessity, of capitalism in organizing human cooperation at scale, and urges the consideration of some problems inherent in capitalism. Munger claims every flaw in markets is worse under socialism. Unless you are willing to advocate monarchism, or actual communist dictatorship, markets and democracy are the only two mechanisms we have for organizing society.