I need a pop3 email account setup that does not have the @domain.com in the username. It's for a piece of software that I am using that does not like seeing @domain.com in the username for setup. Any idea's? The account only needs to be accessed locally.
Gmail supports POP3 logins without the domain part. (Except for Google Apps users, of course.)
If your "clumsy piece of software" does not support SSL encryption either, this can be handled by stunnel in client mode:
Try sending it to firstname.lastname@example.org
You need to use the  to specify this is being sent to an IP.
If that does't work, you could change the HOSTS file to map DOMAIN to an IP where the mail server could sit. For example, mail@DOMAIN, and DNS would then understand DOMAIN to goto some IP.
The only problem now is setting up your pop3 to accept this mail into a proper inbox.
If you mean you want to send email to "user" and not user@domain or even user@, you can't pull this off. You need that @ sign, unless you're going to write your own SMTP layer.