Metallica drummer Lars Ulrich on Wednesday will deliver a literal truckload of paper to Napster Inc. listing hundreds of thousands of people who allegedly use the company's software to share unauthorized MP3s of the band's songs.

The hard-rock group wants Napster to stop the users — all 335,435 of them — from trading Metallica tracks.

On its Web site (www.napster.com), the company promises to terminate the accounts of users who trade material without permission but requires copyright holders to notify them of who is doing the unauthorized trading.

"We're giving [Napster] what they asked for," said Gayle Fine, a spokesperson at Q Prime, Metallica's management company.

Metallica representatives compiled the more than 60,000-page list of Napster user IDs during the weekend. Real names are not included in the list. Q Prime said Napster users are offering 1.4 million MP3 files of 95 Metallica songs.

The band sued Napster and three universities last month, claiming that they enabled copyright infringement by allowing students to use the company's namesake software to trade near-CD-quality MP3 files of such Metallica songs as "The Memory Remains" (RealAudio excerpt). The band promised to drop the case against the colleges after the schools pledged to restrict Napster use on campus networks.

In court papers, Metallica said it would amend the suit with the names of additional universities as well as individual Napster users. However, the user names Ulrich intends to hand over will not be added to the suit, Fine said. Ulrich and a lawyer for the band will deliver the behemoth list to Napster's San Mateo, Calif., offices at noon PDT Wednesday.

Napster has upwards of 10 million users, according to Liz Brooks, the company's marketing vice president. A spokesperson for Napster could not be reached immediately for comment on Metallica's list.

According to Q Prime's data, the most popular Metallica tracks among Napster users are "Nothing Else Matters" (RealAudio excerpt), with 73,772 users sharing; "Enter Sandman," with 72,257 users sharing; and "No Leaf Clover," with 59,842 users sharing. The statistics don't distinguish between studio recordings and live versions from last year's S&M album, Fine said. The band excluded from its list the more than 38,000 users who were trading audience recordings or bootleg albums, unless a particular user also was trading commercially released material, Fine said.

Simply searching for unauthorized files and blocking them may not be a viable solution to copyright infringement via Napster, according to Steve Jones, an intellectual property expert and head of the communications department at the University of Illinois at Chicago.

"The instant that Napster would do this, I wouldn't put it past people with those files to change the file names," he said. "So they decide instead of calling them Metallica, they'll just turn the name backward, and wink wink, all the Metallica fans are going to know."

In recent weeks, Napster has become the epicenter for the debate over online music piracy. In addition to Metallica, rapper Dr. Dre has also recently sued Napster for copyright infringement. The Recording Industry Association of America filed suit last year.

But artists such as Public Enemy leader Chuck D and punk-rockers the Offspring have spoken out in favor of the program, saying it promotes CD sales. Rap-metal outfit Limp Bizkit have taken the company on as tour sponsor for their free summer outing with rappers Cypress Hill.

Metallica will answer fans' questions about the suit in an online chat Tuesday at 5 p.m. PDT at the Artist Direct Network (www.artistdirect.com) and Yahoo! Chat (chat.yahoo.com).