One of the best online resources I've discovered to locate hard-to-find African American newspapers is on GenealogyBank's website at http://www.genealogybank.com/static/african-american-heritage.html.

There are over 250 African American newspaper titles covering more than 150 years of United States black history available there. All these newspapers are fully searchable online.

Here are some of the top African American newspapers for exploring black heritage that they have in their database:

Advocate Newspaper
Advocate Newspaper
Afro-American Newspaper
Enterprise Newspaper
Gazette Newspaper
Independent Newspaper
Sentinel Newspaper
Western Star Newspaper
World Newspaper