How do you find out the mailing address of a person from their email address?

There is no way. Most people like the idea of remaining anonymous via electronic mail. However, ISPs know their customers' mailing addresses as well as many of their customers' e-mail addresses, but this information is confidential. Moreover, people using internet e-mail boxes such as hotmail and Yahoo have complete anonymity provided they setup their accounts properly and watch what they do on the Web.