Great resources for teaching the LBJ and the Voting Rights Act: 

LBJ Presidential Library  http://www.lbjlibrary.org/

   Housed in Texas, they have a great audio and visual section on their website

Texas Young Lawyers Association - TYLA  http://tyla.org/

  Another resource from Texas, TYLA has a great video called Vote America that covers the Voting Rights Act.  Search for the video in the search bar.