More than a year after its expected launch, free P2P music service Qtrax has finally gotten off the ground with deals with all the major music labels. Universal, EMI, Sony, and now Warner Music Group are now all on board with the ad-supported service, and things can finally get rolling... once the software becomes available, that is.

Qtrax was originally slated to launch in January 2008, when it overconfidently boasted of having deals with the Big Four labels. It turns out that none of those deals had been signed yet, reportedly annoying the record labels and pushing the launch date back indefinitely. In February, Qtrax CEO Allan Klepfisz insisted that the music was still coming, but the first music deal didn't land until June. Qtrax spent the remainder of the year trying to hammer things out with the remaining labels, bringing us to where we are today.

Qtrax works by offering free, legal music downloads via the Gnutella P2P network. The music is supported by advertising on the site, though don't go thinking that it's DRM-free or that your usage won't be watched. Qtrax music employs Windows Media DRM that will not only prevent copying to your friends' computers, it will also track how many times a song is played and by which artists. Presumably, this is to figure out what kind of music you like the most and target the site's advertising better, though the company also says that the artists and labels that are played the most will get the largest payments out of the pool of ad revenue.

The problem with that, as we found out last year, is that P2P users are unlikely to go for DRM-laden music files when they could just as easily get DRM-free music from the very same network. The other obvious limitation with using Windows Media DRM is that the music will obviously not work with the largest group of portable music players in the world—the iPod, of course—though it will work with a handful of others.

Still, the company seems eager to get things going after such a long and embarrassing delay. "We had a somewhat embarrassing launch," Qtrax CEO Allan Klepfisz told the Associated Press (via PaidContent). "Now, we clearly do want to make a lot of noise."

Qtrax says that some 300,000 users have been participating in the beta of the service, though Qtrax's beta software was recently pulled in anticipation of its (still-impending) 1.0 launch. There's a note on the site saying that beta users should continue downloading music, but there is currently no way for new users to join in on the fun. In the meantime, potential customers are left checking out the available selections on Qtrax's site or following links to Amazon's MP3 store where they can buy the DRM-free versions.