This link http://scholarlyoa.com/publishers/ shares a list of questionable open-access scholarly publishers. It is known as Beall's List and was created by Jeffery Beall, an academic librarian involved with scholarly communication and located in Denver, Colorado. The list is meant to serve as a cautionary guide for persons who intend to publish or use open-access publications.
Also note that the Directory of Open Access Journals (DOAJ) see http://doaj.org/ will prove useful when checking or establishing legitimacy of scholarly open-access publications.