Directory of Open Access Journals (DOAJ) - is an online directory that indexes and provides access to high quality, open access, peer-reviewed journals. Provides free, full text access to over 10,400 journals, over 6,200 which are searchable at the article level. 

Open Access Journals - provides a directory to major Open Access collections available on the web.

SpringerOpen - launched in June 2010, includes Springer’s portfolio of 160+ peer-reviewed fully open access (free) journals across all disciplines.