American Museum of Natural History
American Museum of Natural History: O Logy: Stuff to Do: Edible Earth
Take a look at the layers that make up our Earth: inner core, outer core, mantle, and crust. Then have fun making a model of the Earth's interior that you can eat up.
The Tech Interactive
Tech Museum of Innovation: Inside the Earth
As an overview of the online exhibit on earthquakes, this site discusses the various sections inside the Earth. The crust, the mantle, and the core are each individually discussed.