Open Access is nothing new, the original call for peer reviewed scholarly literature to be freely available with unrestricted use came in 2002 by the Budapest Open Access Initiative Open Access with a request for:
"free availability on the public internet, permitting any users to read, download, copy, distribute, print, search, or link to the full texts of these articles, crawl them for indexing, pass them as data to software, or use them for any other lawful purpose, without financial, legal, or technical barriers other than those inseparable from gaining access to the internet itself. The only constraint on reproduction and distribution, and the only role for copyright in this domain, should be to give authors control over the integrity of their work and the right to be properly acknowledged and cited." http://www.budapestopenaccessinitiative.org/read
However there has been a recent renewed emphasis on access to research following the publication of the Finch Report in June 2012 which reported the findings of an independent working group which had the objective "to expand and improve access to research publications for the benefit of all who have a stake or interest in research and results”. The recommendations of the Finch Report has led research councils and funding bodies to require that research which they have funded is made openly accessible.
There are two primary ways to publish a paper as open access; Green Open Access and Gold Open Access
Green Open Access, sometimes called self archiving, is achieved by posting the article postprint or preprint into an institutional or subject repository, usually after an embargo period, with no payment of costs.
Article Processing Charge (APC) - the fee that is paid to the publisher by the author, their employer or their funder to allow immediate (gold) Open Access
Creative Commons Licence - a system of licensing that allows copyright owners to specify different levels of rights protection for their work
Double dipping - an institution pays twice for a Open Access journal article; firstly through the institutional subscription and secondly the APC if an author wishes to make their particular article open access
Embargo period - the length of time before a publisher will permit the posting of the postprint of an article into an Open Access repository. See Sherpa/Romeo for more details of embargo dates for individual journals
Institutional repository - an Open Access archive, organised and maintained by a higher education institution, giving access to the research outputs of staff within that institution. Subject repositories are also available (see Open Access resources box opposite for details of some subject repositories)
Post Print - or accepted manuscript. The version of the paper which has been through peer review and has been accepted for publication. See Sherpa/Romeo for details of which version of the article you are able to upload for a particular journal/publisher
Preprint - or author original/author version. The version of the paper as submitted to a journal for peer review. See Sherpa/Romeo for details of which version of the article you are able to upload for a particular journal/publisher