She said that companies such as Apple Computer Inc. are proving that legitimate music download sites that are inexpensive and intuitive can compete with peer-to-peer networks.

"iTunes is cool; it's reasonably priced," Ms. Sohn said. "I think if you got the price of a song down to 50 cents or even a quarter, then you'd see the use absolutely skyrocket, because at that point it's not worth it to put up with the inconveniences of the free services."

Paid services such as iTunes are already making headway with teens, 87 percent of whom use the Internet. Those who download music are split equally between paid services and free networks.

And more than a quarter of the free peer-to-peer downloaders said they also use paid services.

The survey also indicates that although teens are aware of the ethical and legal objections to pirating movies and songs, many of them will switch to legitimate services only if they're more convenient than the underground networks.

The Pew survey, conducted in November 2004, included 1,100 youths aged 12 to 17 and their parents and has a margin of error of plus or minus 3 percentage points.

According to the survey, 52 percent of teenage music downloaders agreed with the statement, "It's never really OK to download music or share copyrighted files online without paying for them or getting permission."

However, most teens don't let that stand in the way of a good download, as 55 percent said they don't care whether the songs they download are copyrighted.

They may be learning that attitude from the adults they know.

In an earlier Pew study, 58 percent of adult music downloaders were equally blasé about copyrights.

"Teens have received a lot of mixed messages recently about what's appropriate," said Amanda Lenhart, a senior research specialist with Pew.

She said that although the recording industry has discouraged piracy and filed nearly 15,000 lawsuits against individual violators since 2003, teens see the proliferation of CD copying technology and portable digital music players as tacit approval for their behavior.

That tension — between content creators who want to decide how you enjoy their products and technology companies that want to sell devices to eliminate those barriers — is only likely to increase.

Apple recently started selling a handful of music video and television shows on iTunes, which previously had been limited to songs and other audio applications. This week, Apple said it had already sold 1 million videos.

Broadcast affiliates have complained about the potential loss of TV viewers, while unions representing actors, writers and directors are contending that they should get a share of iTunes' video sales.

Another collision is brewing with search engine giant Google Inc., which recently said it will resume its project to scan and digitize the contents of library books over the objections of authors and publishers.

Ms. Sohn of Public Knowledge testified before Congress against lobbying efforts by the music and movie industries to limit how consumers can copy material.

She said that although many companies are resisting online distribution, consumer demand will probably force companies to adopt it within five years.

But by then, today's teens may have already found other things to do in their spare time.

Male moviegoers between the ages of 13 and 24 cut their movie viewing by nearly a fourth this summer compared to the summer of 2003, market research firm OTX reported last month.

According to the Pew report, 4 million teens — nearly one-fifth of the online teenager population — now blog, and 8 million read blogs.

"Most of my friends have one," he said. "I have some friends that are obsessed with it, and they have MySpace and Facebook and Xanga. They'll have like four or five different ones."

Many teens also use the Internet to share content they've created — such things as photos, poems and drawings.