The Budapest Open Access Initiative (BOAI) was signed on 14 February 2002. Its goal is to encourage an international effort to make research in all academic fields freely available on the internet. It defines open access as “the world-wide electronic distribution of the peer-reviewed journal literature and completely free and unrestricted access to it by all scientists, scholars, teachers, students, and other curious minds.” This definition is not limited to articles published in journals but also encompasses pre-prints (discussion or workings papers as we call them in Economics).
The Directory of Open Access Journals (DOAJ) list (as of the writing of this post) 3289 journals, including 68 in Economics, that satisfy the requirements of BOAI. While Economics is relatively underrepresented, the working paper culture in our field allows to find in open access many, if not most, of the articles published in non-open access journals (RePEc tries very hard to identify links between different versions of the same work). In fact, most publishers explicitly allow authors to publish pre-prints or post-prints of their articles in institutional repositories, including working papers series. A good list of policies by publishers can be found at RoMEO.
If you think this is a good initiative, you can sign the BOAI here. Foremost, make sure your publications are available in free access through a working papers series, or absent this option, through the Munich Personal RePEc Archive. In particular, in most cases, authors should not remove their working papers once their are published in journals.