Thats actually an awesome idea! the FB phone rumors were around for a while, then died. I guess FB realized everyone already has IOS/Android device... but they never seemed to pat into video a right way, just yet.

if there is none already, somebody could build a skype-type iPhone app to talk/videochat only with your FB connections. If that gets traction, it may be bought by FB, given they wont shut down the API connection.

Wish I would know Cocoa...