iCloud is coming.

Apple is kicking off its Worldwide Developers Conference next week with the unveiling of its cloud-based service, iCloud.

On June 6, a keynote address will reveal the details before a packed house at the WWDC in San Francisco. In addition to iCloud, Apple said it will detail its next-generation desktop operating system, Mac OS X Lion, as well as iOS 5, the next version of the mobile operating system running on its iPhone, iPad, and iPod Touch.

The company also indicated in today's press release that CEO Steve Jobs, who is on an indefinite medical leave, will be on hand for the announcement.

Jobs' decision to participate in WWDC comes just a few months after he made a surprise appearance at his company's iPad 2 unveiling. It was his first appearance since earlier this year when he announced his third medical leave of absence. Jobs, a survivor of pancreatic cancer, has yet to divulge the reason for his leave of absence. He promised earlier this year to return to day-to-day operations at Apple as quickly as he could.

Apple stopped short of providing specifics about iCloud in this morning's announcement. However, details and intimations surrounding the launch of such an offering have been cropping up for quite some time--at the very least since Apple acquired online music-streaming service Lala a year and a half ago.

In January 2010, music industry sources told CNET that they were in talks with Apple for a cloud-based, streaming music service that would allow people to listen to their tracks over the Web on computers and Apple's mobile devices.

Two weeks ago, CNET's Greg Sandoval learned that Apple had signed a cloud music licensing agreement with EMI Music and was closing in on deals with Universal Music Group and Sony Music Entertainment. The company had already reached a cloud deal with Warner Music.

A possible sticking point is that licensing deals with the record companies are only part of the puzzle. Apple also needs to reach agreements with music publishers.

In today's announcement, Apple did not specifically say that its iCloud service will revolve around music, referring to it tersely as a "cloud services offering," perhaps suggesting that it may have more than one function.

But Apple may not want to wait too much longer to launch a cloud music service. Web heavyweights Amazon.com and Google are already getting in on the action. However, those companies launched their services without securing music licenses, putting them at a potential disadvantage against Apple's upcoming offering.

Apple's confirmation today that its cloud service will be called iCloud further bolsters reports last month that said the company had acquired the iCloud.com domain name from Sweden-based "hybrid cloud computing" provider Xcerion. Those reports claimed Apple spent $4.5 million for the iCloud domain, but neither Apple nor Xcerion has confirmed that.

Apple did not immediately respond to CNET's request for further comment.

Update at 6:15 a.m. PT and at 8:00 a.m. PT to add background.