Education in Second Life
Jo has built a community of educators exploring the educational uses of Second Life and other MUVEs on the Islands of Jokaydia - http://jokaydia.com/ in SL. I don't spend much time in-world these days, but I suggest you drop in and say hi. Jo and others in the community give talks regularly.
You will also find many helpful educators at ISTE's (International Society for Technology in Education) island - http://www.iste.org/secondlife/
I would also recommend Alan Levine or Larry Johnson of the New Media Consortium. They have built a massive educational community in Second Life and are looking at other platforms - http://sl.nmc.org/
If you haven't already done so you should join the Second Life Educators' Mailing List (SLED) - https://lists.secondlife.com/cgi-bin/mailman/listinfo/educators - which is the central contact point for educators in SL. You will find plenty of potential speakers there.
You may be interested in the "Education-focused Virtual Worlds" section of the list of virtual worlds I've compiled - http://sleducation.wikispaces.com/virtualworlds" (http://blog.p2pfoundation.net/an-update-on-p2p-technology-education-and-virtual-worlds/2008/04/23)