Facebook on the blackberry use to sync events and Birthdays into my Calander, can't seem to figure that out for the iphone, i see where to sync contacts but that didnt add any events or birthdays to my Calander
I'm not sure about Facebook sync but I know there was an issue about it. Once you synced, it will pull all your contact info and populate to your FB and leaking confidential info like phone numbers and such so if I were you I would stay away from it until they find a patch...
Apple and Facebook don't allow that for privacy reasons. The best you can do is FB Sync. It pulls profile pictures,address,occupation,birthdays. The only thing is you don't get birthdays to you calendar just to their phonebook entry. But the FB Sync app does keep a little directory of birthdays so you can view it for the latest birthdays.