All the sessions from the Mix06 conference at the end of March are now available online.
In addition to IE featured in the keynote there are the following IE specific sessions:
There are lots of other great sessions and I'm going to e spednign a little time catching some ofthe sessions I missed while I was there.
P.S. There's also a great video on Channel 9 on CSS in IE7 that has just been posted featuring Markus and Yin who work on that area.