I believe the following should be the same for both WP 8.0 and 8.1 Dev Preview. I've been running 8.1 since May so I can't remember if it was different in 8.0...
In settings, go to email + accounts. Is FB listed as an account here? If not, add your FB account to your phone.
Next, while in settings, notice the applications heading to the right. Tap it or swipe right-to-left to see the applications settings. Tap people, then filter contact list to verify your FB account is checked.
09-02-2014 08:29 AM