For the last few months Microsoft has been running Windows 8 free developer events around the world (Dev Camps) called 'Windows 8 Camps'. They are still going on so do check the ongoing schedule on the Microsoft site.
If you've been along to one of them you'll have picked up a lot of information about Windows 8, its capabilities and how you take advantage of them in code. The hands-on labs from the Windows 8 Camp have been made available to anyone interested, but until recently the resources were still specific to pre-release versions.
This is definitely worth pulling down. It's an entirely self-contained training lab that takes you through all the steps of building up a nice, functional Windows 8 app. Enjoy!
[ UPDATE: this Camp-in-a-Box runs through the development of a Windows 8 cookbook application called the Contoso Cookbook, along with application. The installable also adds in a variety of useful presentations and resources.
It seems there is also a cut down version of the same kit without the presentations and additional resources at this download link, where the downloads are a little over 60 MB.