Hi Sam!
We had one video call pass using Pidgin to Google talk, so yes, it can be done.
Thats good to know!
What makes you say that the Google library is non-Free? Libjingle, used by Google, is BSD licensed. Is there another Google plugin I'm not aware of?
Maybe I was a bit vague but I'm referring to the Google talk Mozilla plugin and related libs required to use GTalk under GMail. This is my only experience of XMPP so far and you need to install Googles google-talkplugin deb or rpm to enable it as far as I'm aware.
I have not been able to find any source to this so that I might be able to use GMails XMPP/Jingle support under gmail on my Pandaboard for example although I must admit I've not gone to the effort of requesting said source from Google yet. Its nice having it under GMail as you need a browser anyway and if you're a gmail user then its nice not having to install and configure an extra client- it generally 'just works' TM, R etc
So, there are no working XMPP/Jingle clients for neither JACK nor KDE/Qt? :/