So recently (within the last month), I decided that I needed to learn about micro-controllers (basically cheap mini CPUs) so I could move some of My Cool Projects forward. A friend recommended the Atmel STK600 as a good starter kit, so I got one. The good news is that the STK600 is pretty awesome, the bad news is that the documentation for it is abysmal. So I've been maintaining my own "getting started" guide to help anyone else who may want to tread these waters.
You can find my guide here.