[Exim] POP3 Server

I am about to start configuring Virtual Domains, and I believe I have a
pretty good grip on how to get Exim to recognize and handle the email.

Does anybody have a pop3 daemon that they would recommend that will handle
the other side of this? I want an end result that doesn't require a user to
actually be set up on my mail server, but will handle email for multiple
domains.

Thank You
Terry Shows