You can follow the steps below to set up your email on the iphone or you can also view our Iphone Tutorials Videos
On your iPhones home page, open settings.
Then mail, contacts, calendars
Then Add account...
Then other
Then Add Mail Account
On this page, enter your name, your full email address, its password and a description. Give the phone a moment to try and detect your settings.
Then choose imap, and set the following settings:
incoming mailserver: mail.yourdomain.com,
username: your full email address,
password: your password,
outgoing: mail.yourdomain.com,
username: your full email address,
password: your password.

Save this and wait while the iPhone tries to connect to the account (This can take a long time, make sure the screen does not go black by tapping it occasionally).
Continue at the bad cert notice
wait quite a while and you are complete.