Gerd Leonhard has been added to the schedule to give a 20 minute keynote. The content and title is still to be worked out.
Gerd is the author of the 2005 book "The Future of Music" which more recently became "Music 2.0". He is currently working on a forthcoming book called "The End of Control". You can download the work in progress here.
In July 2008, he gave an hour long Google Tech Talk. I've embedded the video of that below:
You can download the 64 Mb .mp4 file here.
For more videos see Gerd's YouTube Channel.