African American Art Song Alliance (includes lists of Composers, Performers, and Scholars)
Beyond Elijah Rock: The Non-Idiomatic Choral Music of Black Composers (Dr. Marques L. A. Garrett)
The Black Music History Library
Black Opera Research Network
The Boulanger Initiative Database
Center for Black Music Research (at Columbia College Chicago)
Explore Music by Black Classical Composers (Theodore Front)
Flute Music by Black Composers
Institute for Composer Diversity (State University of New York at Fredonia)
Music by Black Composers (a project of the Rachel Barton Pine Foundation)
Works by Composers of African Descent (Free Library of Philadelphia - Edwin A. Fleisher Collection of Orchestral Music)
African American Studies Center
Good for background information on specific musicians and genres.
Streaming audio database. They have a list of genres on their home page than can help get you started.
Classical Scores Library
PDF scores available for public domain and contemporary works.
Streaming database of recorded American music. There are about nine albums with music by African-American composers. Enter the search terms African American in the search box.
The nation's largest African American video oral history collection.
Naxos Music Library
Streaming recordings for genres such as Classical, Jazz, Blues, Nostalgia, World, Contemporary Instrumental, Chinese, Pop and Rock, Gospel, Spoken Word, and Relaxation. iPhone and Android apps available.
Streaming music from the artists and collections of Fantasy Records