Well Apple fired the first shot across the bows of the major carriers when they offered iPhone 4s users the ability to send SMS like messages utilizing the iMessage app, thus depriving the carriers the huge profits they have been generating off of SMS.  Now it seems that RIM is doing the same thing with the Blackberry and voice.   Same technology as Facetime, really, but it does allow for you to utilize your wifi to make calls.

Sample screen from the new BBM voice call application.

Suck It, Carriers: BBM 7 Lets BlackBerry Users Talk for Free