On that node, didn’t Apple say, via Steve Jobs at the presentation where it was announced, that FaceTime was to become an open standard? What ever happened to that?
He did, but that’s the last we’ve heard of it as of yet [last I heard it discussed]. I doubt they killed it forever though, it’s not like Apple to make a false announcement (vaporware); it is like Apple to de-prioritize the speed of open sourcing that stack over developing/improving/iterating their own implementation and/or iOS ecosystem as a whole.
For what I understood, the protocols are open, but you can't join in the network without a private key signed by Apple :). It seems to use fairly standard protocols though: http://en.wikipedia.org/wiki/FaceTime#Standards