Although it is only a District Court's order on summary judgment, today's ruling could be huge. Judge Stephen Wilson of the Central District of California granted summary judgment in favor of defendants Grokster and StreamCast Networks (aka Morpheus) and against the entertainment industry plaintiffs. These defendants distribute file sharing software similar to Kazaa which allows millions of users to share copyrighted songs and videos for free.
Basically, the court ruled that, though the software can be and is used to violate copyright, the software companies -- like manufacturers of VCRs and photocopiers -- cannot be held liable for contributory or vicarious copyright infringement. You can read the court's order here. An AP article about the ruling can be accessed here, and law.com now weighs in here.