Yep, both ring.
And if he has more than one Mac then all Mac's ring too.
That's very cool. Skype does the same thing, though.
What intrigues me most about this app is that it doesn't have to be open. It runs in the background unless you actively choose to completely disable it in the settings in osx.
It's sort of skype on steroids. Having it always running will actually make it useful. What I always hated about skype is that ppl forget to open the app.
FaceTime is not revolutionary. Far from it. But apple might just have made video calling more appealing to everybody. Why not cooperate with skype? Integrate it into facetime in some way. Let the video-juices flow!