National Geographic has created a wonderful site for children to explore Grimms' Fairy Tales. Be warned, though, when The Brothers Grimm first collected these fairy tales they were not the sweet, soothing tales you may have read. "The stories collected by Jacob and Wilhelm Grimm in the early 1800s serve up life as generations of central Europeans knew it—capricious and often cruel."
National Geographic's Grimms Fairy Tales presents 12 tales as the Brothers Grimm first collected them. You click on the "Tell Me A Story" link at the end of the page and then you choose what it is you'd like to read about. Depending on what you choose you'll end up at a different fairy tale you can then read.
Don't forget to open the treasure chest while you're visiting the site. When you do you'll read all about the Brothers Grimm and see a map of where they lived in Germany and much more.