On #oggcastplanet on irc.freenode.net, K4k asked about streaming the output, with a webcam shot of the speaker somewhere on the screen.
here's one way to do that.
1st, start the webcam in a non-intrusive frame. mplayer fits the bill here.
~$ mplayer -cache 128 -tv driver=v4l2:width=320:height=240 -vo xv tv://
when that window appears, resize it, place it where you find least intrusive, and set it to remain "on top".
in another terminal, do this
~$ ffmpeg -f oss -i /dev/dsp -f x11grab -s xga -r 15 -i :0.0 out.mp4
then record your screencast.
hit q in the second terminal when you are finished.
If this works.. replace out.mp4 with whatever format or stream you wish to create.
Below is the video I created with this method (on ubuntu 10.04).