Nick MacKechnie, a Microsoftie from New Zealand, says a new beta of IE8 is due sometime before September 30. And this one won’t be just for developers:
We are encouraging site administrators to get their sites ready now for broad adoption of Internet Explorer 8, as there will be a beta release in the third quarter of this year targeted for all consumers. To learn more and get started, please follow the step-by-step instructions located at the following link: http://go.microsoft.com/fwlink/?LinkId=120024 .
Strange, but I would have expected to read that news on the IE Team Blog. For what it’s worth, I’m fairly certain that IE8 and Windows 7 share that milestone. A solid consumer beta of IE8 will be a must-have for a beta release of Windows 7.
Let’s see, IE8 beta in Q3. Microsoft Professional Developers Conference a month or two later, October 27-30, 2008. Yeah, that sounds about right.
Ed Bott 
That is a bummer.. Ive heard in more than one place that IE8 B2 was supposed to be here in early to mid June. Shame on you MS for pushing it back!