This Tuesday May 27th Microsoft released the Preview 3 build of the ASP.NET MVC framework. This build includes some additional features not in last month's drop, some nice enhancements/refinements, as well as Visual Studio tool integration and documentation.
You can download an integrated ASP.NET MVC Preview 3 setup package here. You can also optionally download the ASP.NET MVC Preview 3 framework source code and framework unit tests at http://www.codeplex.com/Release/ProjectReleases.aspx?ProjectName=aspnet&ReleaseId=13792
Read more at Scott Guthries' blog here -http://weblogs.asp.net/scottgu/archive/2008/05/27/asp-net-mvc-preview-3-release.aspx