Apple CEO Steve Jobs took the stage at his company's annual developers conference to tout the new iOS 5, the upcoming Lion edition of Mac OS X and the firm's new cloud service, iCloud.

As expected, the Worldwide Developers Conference (WWDC) keynote focused on software, and unlike the last several years, did not introduce a new iPhone. "If the hardware is the brain and the sinew of the product, the software in the middle is the soul," Jobs said at the beginning of the two hour presentation.

Jobs, who remains on an indefinite medical leave, used his second public appearance this year to demonstrate iCloud, the new free online sync and storage service that for most users will replace the three-year-old MobileMe.

Most analysts and pundits had predicted that iCloud would feature a music streaming or subscription service. But they were wrong.

Instead, iCloud serves as a music, photo, app, document and other data sync service that keeps multiple devices up-to-date with user-purchased or created content.

"I'm impressed," said Ezra Gottheil, an analyst with Technology Business Research, of iCloud. "The price is certainly right."

iCloud will be free to owners of any iOS-powered device or Mac, Jobs said several times during his time on stage.

Unlike the music "locker" services that Amazon and Google launched earlier this year, Apple's iCloud does not require users to upload their tunes to a central server. In iCloud, the tracks are not streamed from such a server, but are instead quickly downloaded at user request to up to 10 iOS devices or Macs, where they can then be played.

"This is the first time we've seen this in the music industry..., no charge for multiple downloads to different devices," said Jobs.

Tracks and albums purchased through Apple's iTunes are available for downloading for free, but to do the same with other music, such as albums that a user has "ripped" from a purchased CD, customers will need to subscribe to "iTunes Match" annually.

iTunes Match doesn't require users to actually upload their music library to a server. Instead, said Jobs, the service scans a customer's collection, matches it against the 18 million tracks in Apple's store, then makes the matches available for instant downloading to the maximum 10 devices or computers.

"This takes minutes, not weeks," said Jobs, taking a jab at rivals Amazon and Google. "If you have to upload your entire library to some service in the cloud, that could take weeks."

Other features of iCloud include contact, calendar and mail synchronisation across multiple devices, a duty the paid MobileMe currently serves, as well as syncing purchased apps, photos and iBook-bought books, storing email messages and documents and backing up selected data.

Document syncing is enabled in the newest versions of Apple's own productivity apps, Pages, Numbers and Keynote, but will require third party developers to revamp their software to use iCloud.

Users will receive a 5GB storage allowance for storing email messages and documents, and for backing up other data.

Contrary to some rumors, which had pegged immediate iCloud availability, the service will launch along with iOS 5 this fall. Developers, however, will get their hands on a beta edition today, as well as access to the APIs (application programming interfaces) necessary to sync data in their programs using the service.

Gottheil applauded iCloud's approach. "It makes a lot of sense.... Apple doesn't want to store all your stuff, but it's going to try really, really hard to make it so that you can easily get to all the stuff you currently have," Gottheil said.

He was even more impressed with Apple's business sense, and saw iCloud as another way the company will leverage its software, or in this case a service, to sell more hardware.

"Apple's saying, 'We want everyone to join our club, but now we don't charge a membership fee. You buy our hardware, and you're in the club," said Gottheil. "Apple will store your data, put your pictures and music where you can get them, all that kind of stuff. 'Join the Apple club and we'll take care of you,' they're saying. 'Don't pay any attention to the price of the thing [the hardware], what you're buying is a way of doing these sorts of things."

During the keynote, Jobs ceded the stage to other Apple executives, who highlighted Mac OS X 10.7, better known as Lion, as well as iOS 5, the next version of the mobile operating system that powers the iPhone, iPad and iPod Touch.