They just sent this out:
http://www.ietf.org/mail-archive/web/rtcweb/current/msg06631... "Google intends to license the techniques under terms that are in line with the W3C’s definition of a Royalty Free License."
(I also see they're playing a bit of the martyr by saying "This agreement is not an acknowledgment that the licensed techniques read on VP8." As if the truth has anything to do with patents.)