Very nice
Did what it says, which is great seeing as how the iPhone FB app is completely lame on birthdays.
Although useful only at install time, a "check all" feature would be nice. I only have 150 friends, but I have friends with thousands, and it would be PAINFUL for them to set up first time.
Also, I hope the app is smart enough to help me find friends birthdays when I add new friends. Id worry about duplicating ones already in my calendar.
SayPlugh about
BDayCal Synch for Facebook Birthdays, v4.0