It has finally come to this: labels are simply giving their music away.

A new Web site named SpiralFrog.com allows visitors – with label approval – to download music free of charge. It launched Monday in the U.S. and Canada after a beta-testing period.

The fine site features more than 800,000 tracks and 3,500 music videos, and promises hundreds of thousands more soon. It makes money through advertising, rather than by the 99-cent downloads popularized by Apple’s iTunes.

The service, founded by Joe Mohen, pays record companies part of its advertising revenue. Thus far, Vivendi SA’s Universal Music Group, the world’s largest record company, is the only major label to dip its tunes into SpiralFrog’s pool.

Songs from several big acts can be found, including Maroon 5, Rihanna, Gwen Stefani, Weezer, Amy Winehouse and Kanye West. All the tracks from many albums are available (from the Who’s “Who Sell Out” to Nirvana’s “In Utero”) so the content here is no small potatoes.

It’s been a hard decade for the music industry. Since the debut of Napster, the music business has seen its revenues dwindle as fans continually find music online for free. Though file-sharing sites in the Napster and Kazaa mold were eventually made to cow to copyright laws, sites that utilize BitTorrent technology have persisted in often making music, TV shows and movies easily available.

The end result is that most albums, often ahead of their release date, can be found free online for anyone with the patience for the search.

So now, even though the Recording Industry Association of America has sued thousands of people for illegally downloading music without charge, the labels are experimenting with doing just that: giving away their product.

Perhaps it’s overdoing the doom and gloom to suggest SpiralFrog symbolizes the music industry’s desperation . After all, giving listeners a free taste of bands is nothing new. Songs have always been broadcast on the radio – where revenue comes from ads – and streaming music is common on sites like MySpace.

Television is a medium that has always primarily functioned by making money from commercials, so why can’t music?

SpiralFrog also places limits on how users play the music they download. A visitor is required to register before downloading. Songs come with copy protections and cannot be burned to a CD. Music can be transferred to some digital music players, though not Apple’s iPod.

Nevertheless, for anyone who has spent their life passionately, obsessively collecting music, it simply feels wrong that something so valuable, so prized, has sunk to the level of the giveaway. Music is more than mere “content” to drive eyeballs to banner ads, but it’s hard to envision Spiralfrog becoming the norm.