Making a notification bubble pop up.

[Neil Woolford]

I do a little remote maintenance of a couple of Ubuntu systems by logging in
with a new NX session.  I have had users think that the sudden increase in disc
activity and slowdown in system response time (they are low powered systems)
means that they are under attack from the internet, and they've shut the system
down for safety.

I know I could ring up and say I'm about to do maintenance, but really I'd like
to pop up a notification bubble to say that it is just me doing maintenance. 
(None of the users is into IM, so I can't do it that way.)

I suspect that Python can drive libnotify0 to send this via dbus to the
notification-daemon, but I haven't been able to find details of how to do this.
 I'm also very much at the beginner stage with Python.

Does anybody know of information or existing scripts that I can use to generate
a system that pops up notifications rather like the "Updates available" bubble
and tray icon?

Neil