1. In your iPhone, go to Settings-> Mail, Contacts, Calendars and go to Add Account. From the selection shown, choose "Other".
2. Enter the required information as you see on your screen and confirm by pressing "Save".
3. Click on "POP". If you have correctly entered your information in the previous screen, all the fields here should already be filled in for you.
Fill in the required fields as you see on the picture below but with your account information. Then click on "Save" to confirm.
4. After a few seconds, if the following screen will pop up. Click on "Yes".
Enjoy using Webmail in your iPhone!