It is definitely available today and I believe it was available shortly after the announcement.

The text-to-text model is available. And you can use it with the old voice interface that does Whipser+GPT+TTS. But what was advertised is a model capable of direct audio-to-audio. That’s not available.

Interestingly, the New York Times mistakenly reported on and reviewed the old features as if they were the new ones. So lots of confusion to go around.

When you go into the regular, slow, audio mode there's a little info circle in the top right corner. Over time that circle has been giving periodic updates. At one point the message was that it would be delayed, and now it's saying it's "on it's way" by the end of fall.

Not perfect but they've been putting their communications in there.