Here is the site to all the songs: http://www.youtube.com/playlist?list=PLkFXQnAzKU78Hz2833mKnet48DwqAuPD7
You can also check out his other projects here: http://lodgemccammon.com/themusic/educational/social-studies/ These projects include the US Constitution, Bill or Rights, 5 Themes of Geography, The Civil War, World War II, and much more.
Not a Social Studies teacher? He also has great resources for Science and Math. Check them out here!