For months — years even — Apple fanatics have been speculating about the mysterious iCloud. Soon, all will be revealed. On Monday, Apple made an uncharacteristic pre-announcement, saying that the company would unveil iCloud at its annual Worldwide Developers Conference on June 6. More characteristically, the announcement offered little information about exactly what iCloud would be, other than calling it "Apple's upcoming cloud services offering." Of course, tech commentators have taken it upon themselves to flesh out the iCloud details. Here, four iCloud predictions:

1. It will store music
Many expect that the iCloud will act as an online music locker that will allow users to access their iTunes music from any device, whether or not the music is saved to that machine's hard drive.

2. And lots more
"It will be more than just music," says Erick Schonfeld at TechCrunch. "In fact, iCloud will likely replace Apple's so-so MobileMe service." For $99 per year, MobileMe syncs a user's email, contacts, and calendars across multiple Apple gadgets. Its 2008 launch was marred by technical issues, much to the dismay of Steve Jobs.

3. It will best the competition
Amazon and Google both beat Apple to the cloud music game, launching their own services in the past couple of months. But Jobs and Co. might win in the end. Apple has reportedly made deals with several major record companies, which could allow the iCloud to automatically scan a user's hard drive for music, and then automatically "mirror" the music library to Apple's cloud servers, says Greg Sandoval at CNET. Amazon and Google require users to manually upload each song — "an arduous process." When the iCloud scans a user's library, it might also detect any songs that are of poor quality, and automatically replace them with better versions, say Brad Stone and Andy Fixmer at Bloomberg Businessweek.

4. But iCloud will cost you
"While it may be a huge shift, it won't be free," say Stone and Fixmer. Apple has surely paid the record companies millions to make iCloud a reality, "and it's unclear how much of those costs it will eat or pass on to consumers."