I will be giving a workshop on Arduino shield design this thursday (24 March 2011) at Metrix:Create Space in Seattle. You can register in person at Metrix or over the phone. I'll be covering the basics of designing and building your own shields, with a motor shield demo project. The cost is $50. Participants will need a laptop, an Arduino, and a USB cable. A protoshield and other required components and tools will be provided. Hope to see you there!