Not too long ago I heard a story on the radio raving about how well folks are transitioning children books to iPad apps. Basically what it is expanding upon is the idea that if your kiddo is going to be entertained with an iPad why not have them explore something that is enriching? A little edu-tainment never hurt anyone.
Take a look! I recommend Oceanhouse Media which has apps from the Smithsonian as well as rights to the entire Dr. Suess collection (including my favorite, The Lorax). Also Scholastic features many classics including the Magic School Bus: Oceans.