If you're experiencing problems upgrading your MVC-projects, check out this blog post. It shows a solution for the upgrade-problems you typically run into:

http://blog.codingoutloud.com/2010/03/02/asp-net-mvc-1-0-visual-studio-2008-project-will-not-open-in-visual-studio-2010-rc-or-beta/

Thanks to Bill Wilder for posting...