Here are examples of what can be found with a little searching (these from the UVA E-text Archive):
Documenting the African American Experience
Three examples of documents that are there:
"A narrative of the most remarkable particulars in the life of James Albert Ukawsaw Gronniosaw, an African prince, written by himself."
"A narrative of the uncommon sufferings, and surprizing deliverance of Briton Hammon, a Negro man."
"Cases adjudged in the Supreme Court of New-Jersey; relative to the manumission of Negroes and others holden in bondage."
Afro-American Sources in Virginia. A Guide to Manuscripts
Database of African American Poetry
And some of the articles to be found in the Historical Text Archive's African-American section:
The Historical Text Archive - African Americans
Lift Every Voice and Sing (1900) by James Weldon Johnson
A Colored Man's Reminiscences of James Madison
An African-American Bibilography: Education
An African-American Bibilography: History
An African-American Bibliography: Science, Medicine, and Allied Fields
Bibliography on Civil Rights and WWII
Congressional Black Caucus, 103rd Congress 1993 - 1994
Gullah Excursion 1993: Ancestral Breaths of Life
I Have a Dream
Letter From a Birmingham Jail
Research Note on the Atlantic Slave Trade Database Project
. . . . . . . . . .