The Directory of Open Access Journals covers free, full text, quality controlled scientific and scholarly journals.
Bielefeld Academic Search Engine is a search engine especially for academic open access web resources. BASE is operated by Bielefeld University Library.
A search tool from EBSCO for open access journals and journals in special programs for developing countries.
Open Access Publishing in European Networks gives access to open access books in the Humanities and Social Sciences.
ROAD provides free access to a subset of ISSN bibliographic records identifying online scholarly resources available in Open Access: journals, conference proceedings and academic repositories.