1865 to Present New Online US History Book

I love the Flat Knowledge US Government e-textbook and am excited that the AP US, 1865 to Present is finally out (with part one due out next Feb).  I would encourage you to look at it thoroughly if you teach AP US as it might be a nice alternative to your current textbook and it is entirely free (they make their money by assuming students will pay for a paper copy (which ultimately, I believe, will not be a winning way to make money).