smARThistory (now part of the Khan Academy) is a free, non-profit, multimedia web-book for art history created by Beth Harris and Steven Zucker. Started in 2005 as a series of audio guides on a blog for use in the Metropolitan Museum of Art[1] and the Museum of Modern Art in New York City,[2] smARThistory today has grown to include video, audio guides, annotated slide shows, images, mobile apps, social media and written content created by Beth Harris and Steven Zucker as well as contributing art historians.

Visit: http://smarthistory.khanacademy.org/