In addition to downloading the ASP.NET MVC 2 RTM, you can also download the ASP.NET MVC 2 source code and futures assembly here. This is Visual Studio 2008 only.
ASP.NET MVC 2 for Visual Studio 2010 will be released in April as a part of Visual Studio 2010.
Hope this helps.
David Hayden
ASP.NET MVC 2 Tutorials and Training