Here's a link to & and a review of a CD that contains numerous civil rights songs:

Voices of the Civil Rights Movement: Black American Freedom Songs 1960-1966   

Various Artists

http://www.smithsonianglobalsound.org/trackdetail.aspx?itemid=29303

"Notes: This double-CD reissue documents a central aspect of the cultural environment of the Civil Rights Movement, acknowledging songs as the language that focused people's energy. These 43 tracks are a series of musical images, of a people in coversation about their determination to be free. Many of the songs were recorded live in mass meetings held in churches, where people from different life experiences, predominantly Black, with a few White supporters, came together in a common struggle. These freedom songs draw from spirituals, gospel, rhythm and blues, football chants, blues and calypso forms. The enclosed booklet written by Bernice Johnson Reagon provides rare historic photographs along with the powerful story of African American musical culture and its role in the Civil Rights Movement. The music of the spirit with the history of the flesh." -New York Daily News

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This site also provides brief sound clips to a number of these songs including, "Certainly Lord".