There’s a slight bug in the iPhone mail setup that won’t let you configure without SSL but there’s a workaround. Here are the steps:
On the iPhone go to Settings> Mail. Choose to Add a New account, enter the user details, choose POP.
Then for the following enter:
Incoming Mail Server:
Host Name: pop.o2.ie
Username: Your O2.ie email address
Password: Your O2.ie password
Outgoing Mail Server:
Username: Can leave blank
Password: Can leave blank
It will then try and configure your account using SSL, it will fail and after 30 seconds ask if you would like to configure without SSL. Choose Yes. It will then give an authentication error. You can accept this but still save the settings that you have entered. It will then give an error telling you that the email probably won’t work, accept this. Go back into Settings> Mail. Choose the O2.ie email account, go to Advanced, turn Use SSL to OFF. Go back and ensure the smtp server name (smtp.o2.ie) is in the smtp field. If you then go back out to Mail on the home screen> under accounts (if you have more then one) your email should then load.
A bit long winded but it works.