"Where we're really focused is getting a broad set of music offerings for consumers," said Robert Hyatt, executive director of premium content for AT&T.
Songs will cost $1.99 each, or $7.49 for five per month. Users who download a song directly to their phones will automatically get an e-mail allowing them to put a second copy on their computers. Customers who have songs through Napster already will be able to transfer them to their phones, Hyatt said.
The new arrangement with the nation's largest wireless phone carrier opens a huge US customer base to Napster. It has smaller deals in the United States and overseas, including one with Japan's NTT DoCoMo.
Napster president Brad Duea said the new service allows the firm to compete more directly with iTunes. "It creates a great base for us," he said.
AT&T plans to make more music content available exclusively for mobile download through deals reached directly with artists.
To launch the service, it will offer content from Grammy-winning band Matchbox Twenty's new album. The group's frontman, Rob Thomas, said mobile downloading is inevitable as users begin to treat their cellphones like the entertainment hubs their computers are.
"It's easy to see where the trail is headed," he said. "This is going to be the way that people are going to get all their media."
He said relationships with wireless carriers like AT&T also potentially shift the way the music business is handled, adding that artists may now be able to find alternative ways to produce, distribute, and publicize their work.
"When you look at the antiquated model that the record company is, it's becoming more and more obsolete," Thomas said.
Only a few mobile users have taken advantage of over-the-air download capability, but some development has been stymied by network speeds, the limited catalog of music available, and disputes over rights management.