Peter Suber in Open Access News has reproduced the text of the motion that the Faculty of Arts and Science at Harvard passed requiring faculty to deposit a copy of their articles with the university.
The Faculty of Arts and Sciences of Harvard University is committed to disseminating the fruits of its research and scholarship as widely as possible. In keeping with that commitment, the Faculty adopts the following policy: Each Faculty member grants to the President and Fellows of Harvard College permission to make available his or her scholarly articles and to exercise the copyright in those articles.
According to another post by Peter Suber, Harvard is the first North American university to adopt an open access policy. He calls it a “permission mandate” (granting permission to the university to make research open) rather than a “deposit mandate.” It has the virtue that the university takes responsibility for maintaining the access, not the faculty member.
More on this can be found here (another Suber post) and here (Chronicle of Higher Ed.).