UPDATE: Video now available at http://blip.tv/file/3840484.
Rather than try and explain how mod_wsgi worked, I concentrated on showing how to setup some basic things, but in doing so deliberately hit all the common problems that some people have with setting up a WSGI application under Apache and mod_wsgi. The slides therefore capture the details of various obscure error messages one will find in the Apache error logs when things do go wrong.
To illustrate issues related to the Python module search path and virtual environments I used Django as an example. The slides therefore are especially valuable if you are trying to deploy Django using mod_wsgi.