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.