How To - Configuring your iPhone for POP/IMAP
On your iPhone, tap Mail or from the Home screen choose Settings > Mail > Accounts > Add Account
Choose your email account type:
Y! Mail (for Yahoo!)
Gmail
Mac
AOL
Other (choose other if you're using SmarterMail)
Click Other
Select a server type - IMAP, POP, or Exchange
Enter your account information:
Enter your email address
The email server type (IMAP, POP, or Exchange)
Enter your incoming mail server (which may look like "pop.yourdomain.com")
Enter your outgoing mail server (which may look like "smtp.yourdomain.com")
Enter your user name and password for incoming and outgoing servers (enter a user name and password for an outgoing server)
Note: replace "pop.yourdomain.com" with your real domain name.