Chris McDonough has posted a great introduction to Repoze that goes into a bit more depth than the initial announcements and screencasts, but is still very approachable. If you're interested in how Repoze works, I recommend you read the PDF.
The Repoze blog is an interesting read in its own right. I've asked that it be added to planet.plone.org to make it easier to follow for us Plone heads. I'm sure Chris and Paul and Tres won't mind. :)