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.
Spayed means a female dog has had her reproductive organs (ovaries and uterus) removed. Neutered means technically that an animal has been de-sexed, but usually is used to refer to a male dog being castrated.