STOCKHOLM - The four men behind the popular file-sharing website The Pirate Bay have gone on trial in Stockholm, Sweden, accused of helping millions of users worldwide break copyright law.

The trial is being watched with great interest by film and music labels and file-sharers around the globe since it could determine at what point file-sharing, or the encouragement of file-sharing, becomes illegal.

The defendants are accused of breaking Swedish copyright law by helping Internet users download protected music, movies and computer games.

The Pirate Bay doesn't host copyrighted content, but directs users to films, music and other protected material through so-called torrents.

Twenty-eight-year-old Gottfrid Svartholm Warg, 30-year-old Peter Sunde, 30-year-old Fredrik Neij and 48-year-old Carl Lundstrom face up to two years in prison if convicted.

They also face a possible fine of 120 million kronor, equivalent to C$17.8 million, in claims for compensation and damages for the artists whose works have been infringed.

Three of the defendants administer the site, while Lundstrom finances it. The number of users is estimated at around 22 million.

The events surrounding the trial have received wide attention. On Sunday, the accused called a news conference, transporting participants in buses decorated with a pirate ship and banners with the words "ctrl+c, crtl+v" -- the computer commands used to perform copy and paste tasks.

They banned certain media from taking part in the news conference because they didn't like some organizations' reporting of the events so far.

The defendants insisted their site is legal and that prosecutors wouldn't be able to shut it down even if they are convicted.

"They have already failed to take down the site once. Let them fail again," Svartholm Warg said.

A special website has also been set up to report information about the trial.

Local media reported that a dozen Pirate Bay supporters gathered outside the packed courtroom Monday, waving black pirate flags.

Plaintiffs in the case include Warner Bros. Entertainment Inc., MGM Pictures Inc., Colombia Pictures Industries Inc., 20th Century Fox Films Co., Sony BMG, Universal and EMI.

The case stems from May 31, 2006, when police raided 10 locations in central Sweden, seizing servers and computer equipment and temporarily shutting down the site.

Evidence in the case includes witness testimony, emails between the accused and invoices sent to advertisers.