There are now several resources available to the budding Windows Phone 7 Series developer.
There are two book previews available:
The videos from Mix are also now available – for detailed insight into XNA game development you must watch Shawn Hargreaves session! Love it. Plus he demonstrates the six effect shaders in Windows Phone – something I’ve seen no detail on anyway else. Top stuff Shawn!
And if you haven’t got your free dev tools preview yet (WTF?) get the Dev tools and the Designer tools!