There's a new player with new ideas in the online music service market: This week, Universal Music Group announced that it's partnering with fledgling music service provider SpiralFrog to offer an iTunes competitor that the companies hope will supplant illegal file-sharing networks. The companies' strategy is simple, if unexpected: The service they'll offer will let users download songs for free.

"Offering young consumers an easy-to-use alternative to pirated music sites will be compelling," said Robin Kent, founder and CEO of SpiralFrog. "SpiralFrog will offer those consumers a better experience and environment than they can get from any pirate site."

Although offering legal song downloads for free sounds implausible, SpiralFrog says it can forgo the usual 99 cent fee per song and pursue an advertising-based model instead. Various niche services have tried similar approaches, but none have been backed by a major music studio. And on top of its access to Universal's millions of songs, SpiralFrog says it's also talking with other recording companies, including EMI, Sony BMG Music Entertainment, and Warner Music. SpiralFrog plans to launch the service in the United States and Canada by the end of the year.

Naturally, the free service will come with restrictions. The songs that users download for free can't be copied to recordable CDs or shared with other users, and users will need to access the SpiralFrog Web site at least once per month to keep their usage licenses refreshed. After six months, the downloaded songs will stop working. And whenever a user starts downloading a song, he or she will have to sit through 90 seconds of advertising first.

In a slap at market leader Apple, songs downloaded from SpiralFrog won't work with iTunes or the iPod. The songs will, however, work just fine in Microsoft's Windows Media Player (WMP) and any Microsoft-compatible PlaysForSure device, including Media Center PCs and Windows Mobile-powered Portable Media Centers.

The service's target audience is 13- to 14-year-olds, "an advertiser's dream," according to Kent. He said SpiralFrog will share its ad revenues with its recording industry partners, such as Universal.