The Google Books Library Project is an effort by Google to scan and make searchable the collections of several major research libraries. If a book is out of copyright and in the public domain, the book is fully available to read or to download.
The Library of Iberian Resources Online (LIBRO) is a joint project of the American Academy of Research Historians of Medieval Spain and the University of Central Arkansas. Its task is to make available to users the best scholarship about the peoples and nations of the Iberian peninsula.
Project Gutenberg is the place where you can download over 30,000 free ebooks to read on your PC, iPhone, Kindle, Sony Reader or other portable device.
The Latin American Studies Association (LASA) is the largest professional Association in the world for individuals and institutions engaged in the study of Latin America.
With over 12,500 open access articles on the "history of Spain," this free resource from the Universidad de la Rioja is a great place to find Spanish-language scholarly articles.
La Biblioteca Virtual de Patrimonio Bibliográfico, or Virtual Library of Written Heritage, is a cooperative project between the Ministry of Culture and the Autonomous Communities with the objective of sharing digital objects like manuscripts and printed books that form part of the Spanish Cultural heritage.