The U.S. Copyright Office has published rules governing exemptions to the DMCA, including provisions for educational institutions and libraries.
The Librarian of Congress, on the recommendation of the Register of Copyrights, has announced the classes of works subject to the exemption from the prohibition against circumvention of technological measures that control access to copyrighted works. Persons making noninfringing uses of the following six classes of works will not be subject to the prohibition against circumventing access controls (17 U.S.C. § 1201(a)(1)) during the next three years.
The advent of DMCA has complicated the situation with copyright exemptions. In many cases, the distribution of a work is clearly fair use under previous copyright law, but in order to make distribution possible, “copy protection” schemes must be circumvented first. This sort of circumvention is generally prohibited by DMCA. So it helps to know, straight from the source, that the preparation of digital content for normal fair use is also legal.