Apple is integrating Facebook features into the Apple iPhone OS 4. The features will mostly be announced at the Apple Worldwide Developers Conference on June 7 along with the new Apple iPhone.
A Facebook contact feature is most likely where the user can access the Facebook id of his/her contacts.
Apple might also add Facebook Connect to their SDK so that developers will be able to add Facebook social functions to their applications.
The moves comes as no surprise since just last month we saw about 34.2 million active users of the Facebook iPhone application. Thats nearly 10% of the total number of Facebook users!