The BBC Magazine has an interesting discussion story about VoIP and how it is changing communications.
By recognizing that the paradigm has changed from dial, talk, hang up, it is showing that how voice communciation is changing.
Free services like Skype, SipPhone, Firefly all now mean that instead of typing and chatting via an IM client, you can now "talk" to the other party in real time. For those who are "always on" the phone becomes less and less of the primary means of communication with tools like email and IM at their disposal. Now with high enough voice quality being available for free think of these new VoIP services as the intercom for the distance workers.