I had a D600 with O2 email, the settings went something like this:
Email Profile settings:
APN: payandgo.o2.co.uk
Login ID: payandgo
Password: password
DNS1: 193.113.200.195
Email Account settings:
Account name: O2 Mail (Or wotever ya want)
User name: (Just appears on Emails, serves no purpose really)
Email address:
username@o2.co.uk
User ID:
username@o2.co.uk
Password: Your password
SMTP server: smtp.o2.co.uk / Port 25
POP3 server: mail.o2.co.uk / Port 110
Hope that helps, you got a different phone but you should be able to use these settings. Good luck.