[expert] Mail Server - Very Interested In Setting Up, But....

[Sevatio Octavio]

I'm looking at setting up a mail server but I'm a bit confused about a few things 
(regarding this subject).  What's the difference
between SMTP and POP3 servers?  Is one dependent on the other?  Can they both send and 
receive?  Are some of the POP3 servers easier
and quicker to setup?

Seve