Using telepathy-gabble's (our XMPP backend) Jingle implementation, and telepathy-stream-engine with the Farsight GStreamer RTP library, we got a bidirectional voice/video call going pretty quicklyNow that was a decent hack in itself - video conferencing on a 400Mhz AMD Geode processor - but it wasn't until a week later that Robert went from OLPC to standard laptop video conferencing, to full fledged OLPC XO-1 to OLPC XO-1 simultaneous audio and video transfer.
And it wasn't until this week that Chris Ball achieved the first trans-Atlantic (and trans-Cambridge) videoconference on the OLPC. It's only too bad the experience left him looking like an uber-dork.
Now the next step is multi-user video conferencing, classroom conferencing if you will, on a global scale. Imagine entire country's classrooms, full of children, in a massive multiplayer online conference. An E3 or Computex of students who view source code or explore the OLPC Library of Alexandria.
I just hope that SES Global can handle all that data traffic on its donated bandwidth or there will be a lot of disappointed children (and adults).