A Century of Sound, The History of Sound in Motion Pictures: The Beginning 1876-1932
For those interested in an obtaining an outstanding documentary on the history (form a mostly U.S. perspective) of sound in motion pictures, go to The Rick Chace Foundation Website. From the website: "This educational DVD is now available free of charge ($10 shipping and handling fee) to qualifying institutions, schools, historians, researchers, scholars and other non-profit organizations."
DVD review with screenshots at Summer O' Babylon
Review at David Bordwell's website on cinema
More film sound history and links at FilmSound.org