This guide lists some of the resources you will use as you research Latinos in the United States. To do comprehensive research, you will need to use this guide in conjunction with subject-specific guides such as literature, economics, political science, etc.
The General Info tab provides links to some encyclopedias and other online reference books to help you get background information for your research. It's not a comprehensive list so feel free to use items not here!
Several other libraries have specific pages dedicated to researching Latinos in the United States. A page you will most definitely want to visit is The University of Texas at Austin's Latin American Network Information Center. It has information about Latin America and the Caribbean organized by country and subject. Here is there guide on Hispanic/Latino peoples: http://lanic.utexas.edu/la/region/hispanic/ .