To setup your iPhone to access your email boxes use the following procedure:
Choose "Settings" from the iPhone main screen
Choose "Mail, Contacts, and Calendars" from the settings screen
Choose "Add Account"
Choose "Add Mail Account"
Enter in your name and e-mail address. Then your e-mail password, and give the account a name with the description field.
Select "POP" as the email type
Enter your name or a name that represents the email box (this will appears as the "From:")
Enter the email address in for format firstname.lastname@example.org (with your account and domain)
For both the incoming and outgoing server enter the following:
Enter mail.yourdomain.tld for the Host Name (use your actual domain domain name)
Enter your full email address as the User Name
Enter your password
Once all the information is entered you can choose Save. The iPhone will then try to connect to our email servers. It will try to connect twice (one for incoming and once for outgoing email). If you receive a warning about an invalid SSL certificate simply choose "continue". Once this process is completed your iPhone will be able to receive and send mail from your cPanel Hosting mailbox.