Update README.md

Author: 9swampy

README.md

@@ -2,3 +2,8 @@ SelectedItemsBindingDemo
 ========================
 
 An example of how to bind the SelectedItems property of an ItemsControl in WPF to a ViewModel
+
+The origin of all this and a good explanation of how it all works can be found at 
+http://blog.functionalfun.net/2009/02/how-to-databind-to-selecteditems.html
+
+The original example demo is still included in the code base, but the code has been reorganised a bit so that it can be published as a utility library in a NuGet package. I'm hoping you'll find it as useful as I have done, and making it available as a NuGet package should ease integration with your production code!