To begin new email account setup:

1) On your BlackBerry device, on the BlackBerry Internet Service web
site, on the Services and Settings web page, click Email Accounts.
2) Click Add An Email Account.
3) Type your email address information. Click Next.
4) The BlackBerry Internet Service will not be able to automatically add your email address.
5) Select the I will provide the settings to add this email account option.
6) Click Next.

Summary of the required settings:

Email Address name@yourdomain.com
Account Type POP or POP3
Incoming Mail Server mail.yourdomain.com
Account User Name name@yourdomain.com [your full email address]
Account Password [your current email password]

Some Smartphones allow the following setting:

Outgoing Mail Server Address mail.yourdomain.com