I looked into this earlier, there is not really an official way to get this in python, but there is a partial c binding in another project: http://code.google.com/p/gnome-pulse-applet/source/browse/trunk/GnomePulseAppletInterface/GnomePulseAppletInterface/lib_pulseaudio.py
Which I might be able to use, but of course will add a lot more code.