Microsoft has released ASP.NET MVC Preview 4. It has one of the most awaited release since, Microsoft’s first attempt to make MVC based framework (not Web Forms). It can be downloaded from Codeplex.

Useful Links:

• ASP.NET MVC Preview 4 - Using Ajax and Ajax.Form By Scott Hanselman
• ASP.NET MVC Preview 4 Release (Part 1) By Scott Guthrie