The basic principle works like this: Lala’s technology can instantly match songs from consumers’ personal music library with the Web-based catalog on, thus enabling the user to listen to his tracks. Thos willing to expand their playlist may do so by either adding songs to the webcollection for 10 cents or by buying a DRM-free mp3 file for 79 cents.

“We live our lives in a browser, whether it’s emailing, watching television shows or using Facebook” said Geoff Ralston, CEO of Lala. “When I launched Yahoo! Mail few thought hundreds of millions would depend on Web email. My music belongs online in the same way. Will there be anything without a browser in 5 years?”

Lala’s new service is backed by all four major music labels (EMI Music, Sony BMG Music Entertainment, Universal Music Group and Warner Music Group), plus an additional 170,000 independent labels and distributors.

The service offers over 6 million songs, all of which can be played (once) by the user for free before deciding whether to buy it or not.

The new service supports Microsoft Explorer, Firefox, and Safari browsers on both Windows and Mac OS .