A short but pretty decent introduction to the Raspberry Pi. The book is best suited for complete beginners, but there are still some helpful tips for those with plenty of software experience. I got a free Raspberry Pi at both PyCon and the Erlang Factory.
I also attended a great workshop run by Omer Kilic of Embedded Erlang that included a free expansion board with LEDs, buttons, switches, and a temperature sensor. They are about to release an Erlang-based embedded development environment.