Our very own repi (Johan) is going to be doing a keynote on Mantle tomorrow.
https://twitter.com/repi
http://www.neogaf.com/forum/member.php?u=90936
The overview is below along with his brief bio.
As usual PCPer will be live blogging it. I dont know of any place that would be doing any live video stream unfortunately. Looking forward to it.
http://www.pcper.com/live/
edit: Livestream (thanks FLAguy954)
Hey artist, add this link to the OP. It's where you can sign up to livestream the keynotes today. Just type in your info and what for an email confirmation.