Another thing I have been struggling with over the last couple of years, is getting my BT Connect Email to work on my iPhone, it would work with my Blackberry and Windows phones.
OK. So the bit I was always struggling with was EXCHANGE.
1. Go to SETTINGS, then select MAIL, CONTACTS, CALENDARS, then ADD ACCOUNT
2. Once selecting ADD ACCOUNT, chose MICROSOFT EXCHANGE from the top of the list.
3. Enter your email address (eg. email@example.com) even if you have a domain name attached, use the BT Connect account. Ensure you leave DOMAIN blank.
4. Click NEXT and the iPhone tries to verify settings, eventually a new field will appear called SERVER. Type in EMAIL.BTCONNECT.COM
5. Click NEXT and it will ask you what you would like to sync, you have the choice of Mail, Calendar and Contacts
6. Your email will now work, the latest version of iOS will allow more than one exchange server and more than one calendar book. You can also go into Calendar and select which calendars will appear.