Comment 7 for bug 833382

Ok, so according to Jeremy in that mailing list thread:

"Yes, Ubuntu Oneiric ships GNOME 3; Natty shipped GNOME 2.32. GNOME Panel 3 is available for install in the repositories but panel applets must be ported to gnome-panel 3 or else they simply won't run at all. python-gnomeapplet is no longer being developed as Python developers need to use GObject Introspection instead of PyGTK to work with GTK3."

So this means I'm going to have to dig into the Gnome 3 source code to see how to write an applet, since there is no documentation available :-/

This will take me a few weeks, at least...