Just came across a podcast interview with Maryann Frazier, Penn State University.
It is the Agrovinnovations Podcast Series, episode for 6/9/2008. Free subscription in iTunes - you don't need an iPod to listen - the iTunes software is free, for Window and Mac. I found it via the Apple iTunes store search. It is also available here:http://agroinnovations.com/component/option,com_mojo/Itemid,173/lang,en/
IPV virus seems to be fairly consistently associated with CCD. Pesticides also suspected, and a 'new' strain of nosema may play a role.