ASP.Net MVC framework is an alternative to the WebForms methodology that has been a feature of .Net since the good old days. 

ScottGu has the details of the new preview drop from earlier today.  This falls into that group of things that I'd love to take a deeper look at when I have time :-)

Look for Scott Hanselman talking about MVC at Tech Ed (assuming of course you registered in time).

Link: http://weblogs.asp.net/scottgu/archive/2008/05/27/asp-net-mvc-preview-3-release.aspx