Just a heads up from DevFish (http://devfish.net), a free book on writing applications for Windows 8using html, css and javascript by Kraig Brockschmidt .

You can find the book here:

http://blogs.msdn.com/b/microsoft_press/archive/2012/10/29/free-ebook-programming-windows-8-apps-with-html-css-and-javascript.aspx

I have not finished reading this but so far it looks like it will be a great resource if you have any interest in trying the windows 8 javascript programming model.

Besides all the aspects of controls, library support and animations the book also talks about how to make your own components in c#, vb or c++.