If you can watch only one, watch Eyes on the Prize

Other documentaries worth watching:

http://www.amazon.com/Let-Freedom-Sing-Inspired-Movement/dp/B001XJBDN0/ref=sr_1_1?s=movies-tv&ie=UTF8&qid=1374890690&sr=1-1&keywords=freedom+songs

http://newsreel.org/video/RACE-THE-POWER-OF-AN-ILLUSION

These documentaries are harder to find:

The Lost Year: The Untold Story of the Year Following the Crisis at Central High School, 2007

The Adventures of a Radical Hillbilly: An Interview with Myles Horton by Bill Moyers, 1981

Journey to Little Rock: The Untold Story of Minnijean Brown Trickey, 2001

Fictionalized accounts for adults:

Movies for children: