They were supposed to release version 2.0 by the end of the year, but if it's not out by now, it will probably arrive next year. There's also an Android version planned for next year.
iOS - it can't go there because it's a GPL Apple, and Apple doesn't allow GPL apps on the store. But as far as chatting goes, you can use any other OTR-enabled app like ChatSecure and so on, to talk to the Jitsi client on other platforms. And yes, Jitsi also works on Linux and Macs.
I don't think apple disallows GPL apps per se (in fact if you google gpl apps itunes, there's several hits).
I think it is more of a matter if the app publisher doesn't own the copyright of the work. In that case, other contributors may choose to raise hell regarding the GPL (which is what that Nokia employee did when VLC was briefly in the app store).
But if you own the copyright, obviously you wouldn't hassle yourself for publishing your own app in the app store.
FOSS, cross-platform (not mobile yet though, if you can throw money at that, it can be done), encrypted audio/video, in active development. You can use any XMPP account you like. It even has call recording built in which is very handy if you might need to remember or protocol things.
For speech/video, Skype client is much better than imo, so we still need an alternative for that and although I can find stuff myself; it is either not cross platform (we need Win, Lin, Mac, Android and iOS), too new (not working) or completely impossible to install (not all people using the client are computer wizards). Maybe someone here can advise something for a work situation where we have 3 offices in different EU locations which need to communicate all day with sight and sound? And encrypted ofcourse. After my Skype experience, open source is preferred.
Edit: thanks for Jitsi! Didn't know that one.