King has been at it again.... Keynote Web Viewer Plugin
It's a plugin for Keynote that provides a WebKit-powered web browser component (the same one used in Safari and OmniWeb) for use in Keynote slides. Very slick. It has some limitations at the moment, but it's pretty amazing.
Playing quickly with the first release, and watching the demo movie he made, I had an irrational flashback to Cyberdog...