I've been having a great time perusing through the PyCon 2011 video archives and watching some of the talks. Turns out most of them are 30 minutes long, which is a lovely amount of time -- a bus journey, a late afternoon break, etc, and exactly the length of my attention span :-)
Here's a link to an excellent talk on growing your community of contributors, with actual tried-in-real-life examples and how and why they work and what you can do to improve your own project. In case Python's not your thing, it's actually not very Python-specific ; there are many examples from different communities (Debian, OpenHatch, ...)
PyCon 2011: Get new contributors (and diversity) through outreach by Asheesh Laroia.
"Diversity" sort of remains in the background of the talk, rarely directly mentioned, and I think it makes sense. If you spend the time nurturing new contributors and making sure to create an environment where it's ok to learn, you're more likely to get people from different walks of life showing up.