Cognitive and cultural embeddedness: combining institutional economics and economic sociology
According to this, pederasty is sexual relations between two males, especially when one of them is a minor. Other definitions, like the one that JSBangs found, differ slightly. But otherwise, I think you answered the question yourself: pedophile refers to the attraction, while pederasty refers to the act itself.
Used incorrectly in the media as another word for pedophilia, pederasty is commonly confused for the obsession or desire for child pornography. Pederasty is defined as generally anal intercourse between a man of undetermined older age and a male who is underage, as the restrictions apply in his area.