I was at the Dev Day presentation for Shield. I have a unit, but have received no further communication. Not sure where to start. Where are the developer resources?
Shield is just a standard Android device and as such uses standard Android development tools. I highly recommend starting with the TADP 2r4 download found @ http://developer.nvidia.com/tegra-resources. Please keep in mind that your application will need to support landscape and the controller.
Cheers!