Source
To configure your iPhone (software version 1.x) for email, follow these steps:
From the Dashboard, click Settings.
Under Settings, select Mail.
Select Add Account...
Select Other as the type of account.
Select POP.
Enter the requested information:
Name: the name of the mail user
Address: the email address of the mail user
Description: a description of the mail user
Host Name: enter the mail server mail.yourdomain.com (incoming mail server and external mail server)
User Name: enter the full email address (incoming mail server and external mail server)
Password: enter the users password (incoming mail server and external mail server)
Click Save.
If you see a message that says "Cannot Connect Using SSL", click...