Brian O'Leary, Impact of P2P and Free Distribution on Book Sales, ebook, May 2009. Only this description is OA: See also our past post on O'Leary's research.

Mark Ware, Web 2.0 and Scholarly Communication, a preprint.  Undated but posted by the author May 14, 2009.

Chris Spencer, EThOS - an update, Bournemouth University Library , May 13, 2009.  (Thanks to Charles Bailey.)

UVaDoc is the new IR for the Universidad de Valladolid. See the announcement here (in Spanish).

Philip Davis, Dark Secrets: Open Access and Author Processing Charges, Scholarly Kitchen , May 13, 2009. Comment .  Phil's title and opening sentence are a little melodramatic in light of the results, but he asked two good questions and I'd like to know the answers myself.

John Wilbanks, Knowledge ‘Interoperability’, Beyond the Book, May 10, 2009.

Luigi Benetton, Free vs. paid online legal research tools, The Lawyers Weekly, April 17, 2009. (Thanks to Kristopher Nelson.) Discusses commercial law resources vs. OA sources such as CanLII.

Version 3.2 of Fedora Commons was released on May 11, 2009. (Thanks to Charles Bailey.) See the release notes for a list of changes.

Charles Bailey has released version 75 of his Scholarly Electronic Publishing Bibliography. See the announcement for a list of sections updated.

The Social Science Research Network has launched the Corporate Governance Network, including an OA repository. The section is sponsored by the Investor Responsibility Research Center Institute.

Advanced Research Journals is an apparently new OA publisher.  I say "apparently" because nothing on the site speaks about OA, although a May 5 listserv call for papers in broken English says that ARJ publishes OA journals ("Advanced Research Journals are an Open Access online journal...").  I've seen no press release announcing the launch, even now that I've gone looking.