I presented an overview of the py library last night at our SoCal Piggies meeting. Although I didn't cover all the tools in the py library, I hope I managed to heighten the interest in this very useful collection of modules. You can find the slides here. Kudos again to Holger Krekel and Armin Rigo, the main guys behind the py lib.
And while we're on this subject, let's make py.test the official unit test framework for Django!!! (see the open ticket on this topic)