WPF/E is a cross-platform (POR is windows + mac, linux tbd) subset of WPF that runs in a browser..
At MIX Joe Stegman ( presented the most comprehensive overview and release plans I have seen to date) ... Mike Harsh has posted Joe's presentation here and is keeping track of the post-mix06 buzz.... My favorite so far is at http://ajaxian.com/archives/microsofts-mix-06-conference ...
if you are interested in WPF/E ... please check on Mike's and Joe's blog.. I just subscribed 😉
Also, I hear the MIX sessions will be posted in a few weeks.. Not sure where or when but I am guessing if you monitor the MIX blog, you will find out sooner than the rest of us ..