Cabell's Directory offers the option to search by title, discipline or ISSN. Click on "Filters" to the right of the search box to show the bottom menu, and then click on "Open Access." Each type of OA is also clearly indicated on each title by a color coded unlocked icon. Log into Esearch to access this database.
ISI Web of Knowledge allows users to search and refine by a number of different categories, so they can hone in on their particular research interests. Using these results, researchers can determine the most effective open access journals to place papers. Log into Esearch to access this database.
Limit to OA on left column menu.
Results clearly indicate where open access full text will be located (from publisher, in a repository, such as UT's IR, etc.).
Journal Citation Reports also can be refined by "Open Access" to find the impact factor for select OA journals in your field.