Brewster- Your personalized address book

Brewster is your personalized address book.
Brewster brings together everyone you know across multiple services to create personalized, updated, and merged views of your contacts. Use Brewster to connect the dots you never knew existed and see how your relationships are evolving.

Services included today: Facebook, Twitter, Linkedin, Gmail, iPhone contacts, Foursquare
(note: iPhone Contacts plus Facebook or Twitter required to sign-up)

Link: http://itunes.apple.com/us/app/brewster/id440979190?mt=8