The ACLU works to "defend and preserve the individual rights and liberties that the Constitution and laws of the United States guarantee everyone in this country." These rights include free speech, equal protection, due process, and right to privacy.
"The Berkman Center's mission is to explore and understand cyberspace; to study its development, dynamics, norms, and standards; and to assess the need or lack thereof for laws and sanctions."
The Center sets standards for socially engaged media-making. The site contains research and codes of best practices. Extensive coverage of copyright and fair use.
The CMLP is affiliated with the Berkman Center for Internet & Society and the Center for Citizen Media. The site provides resources for those involved in online and citizen media. Excellent legal guide, blog, and legal threats database.
When Is Free Speech Hate Speech? by 
An Indispensable Liberty: the fight for free speech in nineteenth-century America [electronic resource] by 
Free Expression in America: a documentary history by 
Encyclopedia of the First Amendment by 