The less obvious, but no less important part, however, is software. What will these things run? Twitter apps, tip calculators, weather widgets, and Angry Birds Rio aren't going to help kids learn to read, build an understanding of the world around them, and ultimately create value in society. I'm sure you can come up with a handful of "educational" apps from the Android Marketplace, but for these to really be valuable in schools, they're going to need professionally-developed, curriculum-integrated software, and teachers are going to need to be trained in using it to its potential.
Having a $50/$35/$10 tablet sets the stage for great things, but that's all it does. It enables real advances in education, but it won't make those advances by itself.