I have written the second article in my series on Extending Visual Studio. In this article I describe how to create a Visual Studio Addin that allows you to switch between cpp/h files, WinForms code and designer, XAML and codebehind and so on. You can find the article on the CodeProject here:

http://www.codeproject.com/Articles/324611/Extending-Visual-Studio-Part-2-Creating-Addins 

There is also a direct download page on this blog, you can get Switch from dwmkerr.com by going here:

http://www.dwmkerr.com/page/Switch.aspx