Internet Explorer 8 Blocker Toolkit: Frequently Asked Questions
http://technet.microsoft.com/en-us/updatemanagement/dd365124.aspx
IE8: What's after Beta 2?
["We will release one more public update of IE8 in the first quarter of
2009, and then follow that up with the final release."]
http://blogs.msdn.com/ie/archive/2008/11/19/ie8-what-s-after-beta-2.aspx
NB: There were at least three (3) IE7 Release Candidates before IE7 Final
was released about two years ago so YMMV.