"Many supplier provide Eagle libraries of their inventory.The free version is limited to PCB of 100mm x 80mm but fine for most needs.it is a bit counter intuitive and takes some perseverance to learn, but I have just done so in a few days to a decent standard.The Sparkfun Eagle tutorials are a perfect place to start.There is also Fritzing, but I actually didn't get on with it as well as I am now doing" . . . .