US Newpapers:

Church World Service offers a searchable database of local and national papers in the United States. Simply click here and input your information (generally only a zip code is needed, unless you're searching for a specific reporter), and it will provide you with a list of local papers in your area and the contact information needed to submit letters or op-eds.

Latin American Newspapers:

Comprehensive list of Newspapers in Latin America. Provided by LANIC.