Typically with UNIX machines, you have to have an account to interact with the machine ... much like WinNT/2000. And typically, each UNIX machine has it's own mail server. By having an account on said machine, you probably by default have an e-mail account on that machine.
What I want is a POP3 mail server (SMTP is sending mail, I'm more concerned with receiving with storage capabilities) where I can control the mailboxes/accounts without having to create machine-based accounts. I am currently not aware of any software of this manner that exists.
-SUO