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 a debatable thing, whether it is ethically sound or not. Different countries have different laws concerning it. Pedophilia, unlike pederasty, is without a doubt harmful to the child. It's considered abuse in most countries.