This from io9.com:
Magic is mysterious and ancient, and its workings are often beyond the understanding of mere mortals. But that doesn't mean that magic doesn't have rules.
Every fantasy saga has its own rules for magic, and its own explanations for how the magical arts work. Where does magic come from? Who can use magic, and how? Do regular muggles know magic exists? We dug through 50 or so of our favorite fantasy sagas, and compiled a complete list of the rules of magic in each of them.
Make sure to keep an eye out for an amended version of the chart on io9.com!