News about the recently previewed Model-View-Controller framework for ASP.Net is that a first look Community Technology Preview is due out in a few weeks.
It will form part of the ASP.Net Futures release, which is a product I had a quick look at recently, and includes some wonderful stuff on Dynamic Forms.
For an overview of what the ASP.Net MVC will do there is a recording of a presentation Scott Hanselman did recently here, as well as an overview of the framework by Scott Guthrie here (if you're not subscribed to Scott's blog yet then why not - he provides some of the most concise yet informationful (is that a word?) blog posts imaginable about ASP.Net and associated technologies).
It seems likely that the next release of the ASP.Net Futures will be released soon after Visual Studio 2008 and .Net Framework 3.5, which are both due out before the end of November, so we shouldn't have long to wait.
Other MVC frameworks do exist for .Net, such as MonoRail from the Castle Project. I haven't had a chance to look at this, but it appears to be an attempt at a port of Ruby on Rails like functionality into the .Net environment.