My students regularly use this site as a place to find primary sources. I require students to locate primary sources on the web and to do document analyses in all my classes. The sources on the site are carefully selected and have good annotations.
The site also contains narrative history on a variety of subjects related to African Americans through 1865. These narratives, especially used with the primary sources, could be effectively assigned as required reading upon which to base a 3-5 page research paper.