This is a presentation I gave as part of a mind share at Rackspace. It is just a very basic introduction to Twisted, event-driven programming, and Twisted's flow control abstraction: Deferreds.
Inspired by (Jessica McKellar's Architecture of Open Source section on Twisted)[http://www.aosabook.org/en/twisted.html] and the (Krondo tutorials)[http://krondo.com/?page_id=1327].