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.
Pederasty is between adult and adolescent males. Pedophilia is is the mental state of being sexually attracted prepubescent children, which could mean boys, girls, or both. Historically, pederastism wasn't generally even considered as part of a sexual preference.