(From Peter Suber, A Very Brief Introduction to Open Access, used under Creative Commons license)
Open-access (OA) literature is digital, online, free of charge, and free of most copyright and licensing restrictions. What makes it possible is the internet and the consent of the author or copyright-holder.
In most fields, scholarly journals do not pay authors, who can therefore consent to OA without losing revenue. In this respect scholars and scientists are very differently situated from most musicians and movie-makers, and controversies about OA to music and movies do not carry over to research literature.
OA is entirely compatible with peer review, and all the major OA initiatives for scientific and scholarly literature insist on its importance. Just as authors of journal articles donate their labor, so do most journal editors and referees participating in peer review.
OA literature is not free to produce, even if it is less expensive to produce than conventionally published literature. The question is not whether scholarly literature can be made costless, but whether there are better ways to pay the bills than by charging readers and creating access barriers. Business models for paying the bills depend on how OA is delivered.
There are two primary vehicles for delivering OA to research articles: OA journals and OA archives or repositories.
The Directory of Open Access Journals contains free, full text, quality controlled scientific and scholarly journals, covering all subjects and in many languages.
Pronounced "hah-tee." Over 8 million titles (including books & journals) 2.5 million of which are in the public domain. It was originally conceived as a back up of Google Books and has grown into a cooperative project to preserve library materials converted from print to digital.
OAIster is maintained by OCLC and delivered on the worldcat platform.
A directory of OA repositories
Peer-reviewed scientific and medical research. Includes articles from journals in biology, medicine, and genetics.
The Registry of Open Access Repositories is a searchable directory
White House Delivers New Open-Access Policy That Has Activists Cheering, by Jennifer Howard, Chronicle of Higher Education, February 22, 2013
Scientific Articles Accepted (Personal Checks, Too), by Gina Kolata, New York Times, April 7, 2013
Project Aims to Bring PLoS-Style Openness to the Humanities, by Jennifer Howard, Chronicle of Higher Education, January 29, 2013
Scholars Favor Open-Access Journals, but Some Say Quality and Fees Are Concerns, by Josh Fischman, Chronicle of Higher Education, February 8, 2011
Some journals are run by for-profit companies that have little association with scholarly societies or institutions of higher learning. Jeffrey Beall is a librarian at Auraria Library, University of Colorado, Denver, who publishes a list of potentially or actually predatory publishers. He has been sued by several of these companies, but continues to maintain the list. See it at: http://scholarlyoa.com/publishers/