The Free Expression Policy Project, whose mission is to "analyze tough censorship issues and seek free speech-friendly solutions to the concerns that drive censorship campaigns," has published a report that describes and summarizes many of the copyright battles that have raged over the past couple of years. It is nice summary useful for introducing the subject to those who haven't been following the battles closely. However, the article doesn't really seem to have a coherent view of the interplay of the First Amendment and copyright.
Read the press release (Free Expression Think Tank Releases Guide to Copyright Battles) and, of course, the report ("The Progress of Science and Useful Arts": Why Copyright Today Threatens Intellectual Freedom).