History seems to be on the trailing edge of online education. Somehow, it seems harder to make history interactive than, say, science. But, fear not, there are some good resources out there. Digital History, for example, covers American History from pre-1492 to the present. There is an interactive timeline and each era has links to an online textbook, pictures of original documents, links to relevant websites, podcasts, music, and even a list of relevant movies. There are also printable handouts, lesson plans and quizzes. Their Explorations content, which seems to be a more in-depth look at certain aspects of each era, is still in progress. This could easily be all you need to teach American History. The content is suitable for Middle and High School and is free.