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.
Both Mader and Jennings & Liew credit Horner with being the first theologian (at least in the English language) to suggest that the Centurion and his boy, whom Jesus cured from near death, is a text about pederasty, although Horner does not attempt an analysis of the text himself.