The Directory of Open Access Repositories (OpenDOAR) maintains a list of academic repositories. You can search by repository name, institution or by searching the contents (i.e. article title or author name).
The Canadian Association of Research Libraries maintains a list of Canadian academic repositories.
You may also find repositories on an individual university's website.
Simmons maintains a list of discipline-based repositories and, new in 2015, is CHORUS (Clearinghouse for the Open Reseach of the United States), designed specifically to comply with funder requirements for open access and working with publishers.
Publication agreements with journal publishers usually transfer the copyright of an article to that publisher. The SPARC Canadian author addendum is a PDF file that an author can sign and attach to a publisher's agreement.
The agreement states that the author retains certain non-commerical rights such as the right to make copies for a class or to post the article on a personal or institutional web site while transferring the copyright to the publisher.
Scholarly communications includes all aspects of the production of research and scholarly works - articles, primary data, creative works and more - along with the system whereby the works are created, evaluated for quality, disseminated and preserved for future researchers.
A recent PLoS article "The Oligopoly of Academic Publishers in the Digital Era" (Larivière, 2015) examines the proportion of research published by the top five commercial publishers.
The open access movement transpired as a reaction of the increasing costs of traditional serials which have outpaced library budgets for many years.
The advent of large "big deal" packages provided some relief for libraries as well as providing rich content for library users but the pricing model is simply not sustainable. The American Research Libraries provided some data on costs from 1996 to 2011 in this graph.
Open access publishing is not without cost - the curatorial roles are sometimes funded by associations or institutions, sometimes by commerical revenues from other publications and sometimes by author fees.
Green open access:
This model refers to the availability of repositories where researchers can upload their publications which are made available to the world for free. In reality, repositories are not free (they require servers, staff time, maintenance) and repositories do not provide publisher services like peer review, proof-reading and lay-out. In addition, many faculty researchers need or want the prestige and recognition of publication in a renowned or highly-regarded journal with a high journal impact factor. Repositiories do not provide this.
Green open access often involves acquiring permission from the traditional journal publishers to allow authors to "self-archive" articles and other works in a repositiory, often after an embargo period where the work is only available behind a pay-wall.
There are two types of green OA:
1. institutional repositories - a list of Canadian university repositories
2. subject-specific repositories - Cornell's ArXiv for physics, mathematics, etc. is one of the best-known of these.
Gold open access:
This model shifts the cost from the end-user (often the library) to the researcher by way of "author fees". The rationale is that publishing is a form of the dissemination of research results and, as such, should be part of the cost of doing research and built into the funding. Essentially, the researcher assumes the burden of the cost of publishing.
Author's fees run the gamut from $99 to thousands of dollars, depending on the journal.
Bronze access: articles available at the publisher's website for free without an actual open access licence
Include paid subscription journals with occasional free open access articles. In some cases, publishers may decrease subscription costs based on the number of articles with author fees. This model is rare and seems to be in decline.