You can browse animation samples here in the Metro style samples library.
You can watch animation with metro style apps in the following URLs
Metro style animation with XAML
Metro style animation with HTML5
Good luck :)
I wrote a blog post about WinRT transitions here:
http://www.scottlogic.co.uk/blog/colin/2011/10/winrt-transitions-creating-fast-and-fluid-metro-uis/
They are an interesting new addition to the WinRT XAML framework and make it easy to create fluid animations.
Colin E.