Specifically, the issue at hand is defining the allowed exemptions to the "prohibition on circumvention of access control measures" mandated in subsection 1201(a)(1)(B) of the Copyright Act (for all you legal scholars out there). This is the most hotly debated provision of the DMCA -- through which corporate racketeers attempted to build a legal cage surrounding the fair use doctrine of copyright law, and then lock the cage.
But the DMCA also requires the Library of Congress to re-examine its rules covering this provision every three years. The first rule period covered October 2000 to 2003; the second, October 2003 to 2006. Comments were solicited for both of these periods as well. Whatever changes the Copyright Office makes in response to the comments it receives will be the law until October 2009.
The 2000 rule granted just two exemptions to the anti-circumvention ban: lists of Web sites blocked by software filters, and works which must circumvent access restrictions because the restrictions have malfunctioned. In 2003, the exemption list was expanded to permit disabled people to circumvent access restrictions with screen readers and similar accessibility technology, and to allow circumvention in the case of obsoleted formats. Unfortunately, the language of the malfunctioning-restriction exemption was also narrowed to exclude databases.
To many people, that's not a big list after six years.
Alongside educators, technology advocates, and civil libertarians who lobby to have this prohibitive encumbrance fixed is the American Library Association, which maintains a comprehensive resource site detailing its participation in the rule-making process and its recommendations to the Library of Congress.
The ALA's initial recommendation to the Copyright Office was straightforward -- the law should exempt circumventing access restrictions for any usage that falls under the existing protection of fair use. The Copyright Office rejected this, of course, but the ALA has subsequently worked to document and demonstrate specific harms and chilling effects resulting from the Copyright Office's chosen policy.
It is a slow and painstaking process, but the ALA's work has the long-term effect of widening people's perception of this law. Movie studios and television networks see the entirety of copyright law as a tool for dictating how consumers should pay them money, but the rest of us know that's not true. Frustrating as it has been that this law was passed in the first place, it provides a choice opportunity to demonstrate the real-world ills of bad copyright policy to a majority of people who did not understand the prophets foretelling doom in 1998.
Anyone interested in submitting a comment to the Office should begin by reading the ALA's material for background information. This comment period is not an opportunity to overturn the DMCA, a soapbox for denouncing the recording industry, or an open forum to unload your grievances about the Library of Congress or the US government in general.
An excellent way to participate is to read through the comments submitted by the ALA (at the aforementioned site) and the Electronic Frontier Foundation's Copyright Office resource page. Then, make a list of demonstrable ways the access restriction clause prevents you from doing something perfectly legal under existing copyright law. Students, for instance, are allowed under fair use to incorporate clips of motion pictures into scholarly research -- but the DMCA prevents them from exercising this right by making it illegal to access the clip in the first place.
Be clear and be specific as to how the access restriction clause affects you, and how an exemption restores your ability to complete clearly legal and non-threatening work. Remember, the Copyright Office is not asking whether information should be free, or what you think of big media and file sharing. It has asked for comments on a very precise question, and precise answers are the best way to convince the Office to amend the rules.