Today many of the latest hit songs and movies are a few mouse clicks away on the Internet, and those same justices are being asked to settle a multibillion-dollar dispute about how such items are shared.

Entertainment companies want the court to let them sue the manufacturers of file-sharing software that allows computer users to download music and movies from each other's computers. The companies say such downloads violate copyright protections and amount to stealing.

Lower courts have sided with the software makers, Grokster Inc. and StreamCast Networks, which say their technology should be looked at no differently than a videocassette recorder.

The Supreme Court hears arguments Tuesday and will issue a decision before July.

How the justices rule could redefine how consumers can watch television shows and films and listen to songs that increasingly are delivered in digital formats. Supporters of file-sharing technology say a ruling against the software companies could effectively give the entertainment industry a legal veto over up-and-coming gadgets; they fear the threat of expensive lawsuits could hamper development of new devices.

The case has star power on both sides.

Don Henley, Sheryl Crow, the Dixie Chicks and other musicians are backing the major recording labels, saying their livelihoods are threatened if millions of people can obtain their songs for nothing.

About 20 independent recording artists, including musician and producer Brian Eno, rockers Heart and rapper-activist Chuck D, support the file-sharing technology. They say it allows greater distribution of their music and limits the power of huge record companies.

Regardless of the outcome, it still won't be legal to download copyrighted materials over the Internet without permission, though tens of millions of computer users do so each day. And any ruling won't affect thousands of copyright lawsuits filed individually against Internet users caught sharing music and movies online.

But a victory for the entertainment companies would allow lawsuits that could drive companies that make file-sharing software out of business. It also would effectively overturn rules that have governed technology companies for more than two decades: Manufacturers can't be sued for copyright violations committed by customers using their products illegally.

Dan Glickman, head of the Motion Picture Association of America, said the film industry will keep trying to get consumers to buy legal digital movies. "Consumers want a legal, hassle-free, reasonable-cost way to get their products online," he said in an interview Monday with editors from The Associated Press.

Mitch Bainwol, chief executive of the Recording Industry Association of America, told the AP editors: "We are doing all the things we should be doing to move into this digital age. That is true no matter what the outcome" of the case being heard Tuesday.

The entertainment companies face an uphill battle with the high court.

The trial judge and a U.S. appeals court quoted the Supreme Court in ruling the same file-sharing software millions of people use to steal music and movies also can be used for "substantial" legal purposes, such as giving away free songs, free software or government documents. They reasoned that gave the software's manufacturers protection from copyright lawsuits based on acts by their customers.

In his April 2003 ruling, U.S. District Judge Stephen Wilson of Los Angeles compared Grokster's software to copying machines, which can be used to make both legal and illegal copies.

The San Francisco-based U.S. Court of Appeals for the 9th Circuit agreed, praising the trial judge for his "well reasoned analysis" and warning against the "unwise" expansion of copyright laws.

The trial court and appeals court based their decisions on the 1984 Supreme Court "Betamax" case. The justices ruled Sony Corp. couldn't be sued for copyright infringement if some customers used their VCRs to make illegal copies of movies.

Entertainment companies argue the file-sharing companies should not have blanket protection from copyright lawsuits, especially when they know about and profit from wide-scale piracy. Court documents said some file-sharing software companies earned millions of dollars annually from advertisements built into their software, and ad revenues climb as more people use the software.

Theodore Olson, the former U.S. solicitor general hired by the entertainment companies, said the threshold for liability "is so high that basically if there's any conceivable legitimate use of the system it passes the test. That standard has got to be rejected."

Olson's former law firm represented Sony in the 1984 case.

The case is Metro-Goldwyn-Mayer Studios v. Grokster, 04-480.