My coworker Kurt was asking about this so I’ll post it up here:

If you have Firefox and GreaseMonkey, then install this script.  Go to your Facebook Phonebook, then in your Firefox menu, go into Tools > GreaseMonkey > User Script Commands… > and you’ll see Export Facebook Phonebook. Extract the data, and then POST it to AddressBooker, which will then guide you through merging it into your Google Contacts.

Script by Brad.