Downloading MP3s is Legal

The brief cited an earlier case where noncommercial copying was decided to be protected by law. David Boies, the high-profile antitrust lawyer hired by Napster, cited internal documents he says show the record labels have abused their power to prevent music from being spread using alternative channels. "If you use a copyright to achieve an anti-competitive purpose, you lose the rights to them," Boies said.
Source: CNET News.com