A program dubbed "Wrapster" was released yesterday that allows any kind of file to be listed and traded over the Napster network, even though the system only recognizes music files. Although Wrapster was not developed by Napster, the company has made no move to block the application.

Wrapster joins a growing list of programs allowing the quick, free and wide distribution of illegally copied files. The trend is bad news for record companies, movie studios and software companies that have fought hard to keep their wares from being pirated online.

Programs like Wrapster and Nullsoft's Gnutella, which mimic and expand on Napster, are quickly speeding the erosion of copyright protections online, leaving copyright holders scrambling to keep up.

"(Copyright holders) are aggressively pursuing the issue in the courts," said Peter Schalestock, an attorney with Perkins Coie. "They'd like to keep up with the technology, but that is turning into an arms race."

Napster, a program designed to let Internet users swap music files with one another, has quickly moved to the heart of the controversy over pirated music and online copyrights. The software allows people to share a library of MP3 music files with anyone else on the Napster system and to freely download songs directly from others' computers.

Napster's ease of use and the huge selection of music available through the system have made it a favorite among college students and other communities with high-speed Internet connections. Thousands of people can often be found on the network in the evenings, often sharing nearly a million songs with their peers.

This has infuriated the recording industry, which views Napster as a tool for piracy. The Recording Industry Association of America (RIAA) has sued the company, charging that its software is facilitating the distribution of illegal material. The industry is asking courts for a potentially huge sum of $100,000 per illegally distributed song.

"The overwhelming majority of the MP3 files offered on Napster are infringing," the RIAA says on a Web page explaining its position. "We believe Napster knows this and even encourages it."

To this point, the turmoil has been caused simply by the distribution of music files. Wrapster raises the stakes, however.

The Wrapster program tricks the Napster software into thinking that any file or set of files, including items such as software, videos or games, are MP3 files.

Its authors, unnamed on the Web site where the software can be freely downloaded, provide programming details and encourage people to write similar programs for other operating systems. In a help file, the authors specifically suggest using the software as a means for trading software programs such as Windows 2000.

Napster said it is aware of the Wrapster program but does not yet see it as a problem.

"They really see it as something that's benign right now," said Dan Wool, a spokesman for Napster. "Until it poses some kind of problem, they'll just keep the status quo."

Napster proponents note that Wrapster's search capabilities aren't unique online. A less well-known program dubbed iMesh allows people to swap music, video and other multimedia files. That provides a broader range of options than Napster itself, which only supports MP3 files, but falls short of the capabilities of the new Wrapster technique.

The software also has spawned imitators offering expanded features. Programmers at Nullsoft, the digital music player company recently acquired by America Online, unveiled an open-source effort that, like Wrapster, would allow any kind of file to be shared. Although AOL quickly pulled the project from its site, the code is available elsewhere, and the project may move ahead independently.

"Other programs have already tried to imitate Napster's system and even taken it a step further," said Wayne Chang, a Haverhill, Mass., student who manages Napster's online community bulletin boards. "Wrapster is just ripping off the same idea, except this time disguising the files as the only media that Napster currently recognizes."

The movie and software industries are watching the RIAA's experience closely, aware that they'll ultimately be subjected to the same pressure. They don't face the same risk of widespread piracy today because high-speed Internet connections still aren't common enough to make numerous downloads of their products feasible.

An audio MP3 file could take up to several hours to download over a dial-up connection and just seconds over a cable or DSL modem. A file such as Windows 2000 or a Hollywood movie, however, could take all day over an ordinary modem and potentially hours even over a fast connection.

Nevertheless, the studios and software manufacturers are doing their best to protect their works against copying and to threaten potential pirates with high-stakes lawsuits.

"It's an arms race as long as someone is trying to get around (copyright protections)," said Rich Taylor, vice president of public affairs for the Motion Picture Association of America (MPAA). "The only things that are preventing a full-blown explosion of video entertainment on the Net are the lack of high-speed connections and the need to secure that digital product."