Space Task Force has a (voice, not text) interview with Centennial Challenge's Ken Davidian at the 2007 ISDC. The interview covers the Lunar Lander Challenge, the Regolith Challenge, the Astronaut Glove Challenge, and the Space Elevator Games (Tether and Beam Power Challenges).
If all of the Lunar Lander Challenge money is won at this year's X PRIZE Cup, Ken would like to have some kind of follow-on competition for the X PRIZE Cup. Of course the Challenges will need additional funding to allow something like that to happen, and they haven't gotten any for a long time. NASA is asking for $4M this year for Centennial Challenges, but it remains to be seen how the budget will work out.
Ken noted that although the Challenges aren't an "outreach" or "educational" program, the outreach just happens by itself. People are just interested in seeing real hardware flying and operating. Also, the Allied organizations are all adding educational components to the prizes they manage.