Postfix - The Definative Guide by Kyle Dent published by O'Reilly
In the meantime, Postfix is an MTA not a POP/IMAP server and so will only deal with sending your message to another MTA or to an associated POP/IMAP server. My guess is that you haven't defined a POP server or the local domain.
Did you edit /etc/postfix/main.cf ?
Really, get O'Reilly if your serious about this.