Sparkfun has compiled a list of resources about everything you need to design for manufacture an electronic product.
Let’s be frank: We’ve made a lot of mistakes over the years. In the ongoing pursuit of better-designed PCBs, we’ve dealt with tons of screw-ups, from boards with ill-arranged traces to boards with…no traces at all, actually, and a host of others. Fortunately, by now we feel like we’ve gotten a pretty solid handle on a largely-error-free design for manufacturing process, and we want to help you avoid some of our past mistakes.
SparkFun’s EAGLE resources – [Link]