<p>Is there any HTML5 support in IE8?  Is it on the IE8 roadmap?</p>

According to
http://msdn.microsoft.com/en-us/library/cc288472(VS.85).aspx#html
, IE8 will have "strong" HTML 5 support. I haven't seen anything discussing exactly what "strong support" entails, but I can say that yes, some HTML5 stuff is going to make it into IE8.