Get it while it's hot and juicy, my friends. The second preview for the ASP.NET MVC forum is available at http://popforums.codeplex.com/.
The release notes show what's new, so I won't repeat that here. Overall, I'm feeling pretty good about how it's coming along. I spent a lot of time fleshing out admin functionality, which is about the least exciting thing, but it's a lot easier to exercise the app when you can change stuff via the UI instead of poking around a database.
I would like to have a beta version out in September, and if my spare time continues to be available at the same rate, and my baby boy is happy and healthy (and sleeping in the evenings), I think there's a reasonable shot at it happening. I can see an RC even coming shortly after even. Remember the goal is to get to feature parity with v8.x first, and then go further.