From what I see so far, the facebook API does not allow you to retrieve your friends email address and phone number - it just returns a blank / zero line. If so, how does Hotmail / Windows Live Mail do it? It allows you to import all your contacts from facebook, including their email address and phone numbers.
Yahoo and Hotmail have special Facebook agreements to sync with your online account. Regular facebook apps never allow access to friends email addresses, only current users if email permissions are granted.