Exact details are rather scarce, but Facebook will be launching a music service later this month. That’s right — Facebook may be about to unleash unlimited free music to all its users. Music is enjoyed almost universally, and free music services have been among the fastest-growing on the web — Napster, to name but one.

Facebook is partnering with top music services Spotify, MOG and Rdio to let users stream music on Facebook. Spotify is a service that lets you listen to virtually any song for free on your desktop, with the occasional, but infrequent, ad. Users can pay a small fee to remove the ads or use the service on their phones.

Though Facebook is the world’s most popular social networking service, with more than 750 million users, founder Mark Zuckerberg is keen to increase the amount of time users spend in the Facebook environment.

Music is said to be just one aspect of the strategy to improve Facebook’s “stickiness” and it is also expected to partner with other media content owners such as movie studios.

“They are working on a platform for music where the goal is to create a connective tissue for fans,” said one person familiar with the talks who asked not to be named as plans are confidential.

Facebook has declined to comment on its new music platform before, but in July several technology blogs reported a software engineer had uncovered programming code for a Facebook product called Vibes, for music downloading.

Facebook could give an important boost to its fledgling music streaming partners as they try to compete in a digital music sector dominated by Apple’s iTunes’s download store. Apple is also readying a streaming service called iTunes Match expected to launch soon.

The largest music subscription service, Rhapsody, has about 800 000 paying users after nearly 10 years.

Another senior executive close to the talks said social networking was important to help overcome one of the key challenges for digital music companies: how to help fans discover new music rather than just search for artists and songs they already know.

“Your friends are engaging with you on Facebook,” he said. “It’s the new form of radio or TV.”

The music platform is expected to be unveiled at Facebook’s developer conference, which begins on September 22.