Apple Inc. (AAPL) Chief Executive Officer Steve Jobs introduced a service that stores music and other files online and keeps devices synchronized wirelessly.

iCloud will let users move their digital life from PC hard drives to remote data centers in the "cloud," Jobs said yesterday at Apple's developers' conference in San Francisco. As part of the service, Apple iTunes, the biggest music seller, will let users keep their existing music library in the cloud for $24.99 a year.

"Today it is a real hassle and very frustrating to keep all your information and content up-to-date across all your devices," said Jobs, 56. "iCloud keeps your important information and content up to date across all your devices. All of this happens automatically and wirelessly, and because it's integrated into our apps you don't even need to think about it-it all just works."

The content stored in the iCloud can be accessed across different Apple devices, including the iPhone, iPad, iPod touch, and Mac, or even a PC. "When anything changes on one of your devices, all of your devices are wirelessly updated almost instantly," Apple said in a statement.

The free iCloud services include:

* The former MobileMe services-Contacts, Calendar and Mail-all completely re-architected and rewritten to work seamlessly with iCloud. Users can share calendars with friends and family, and the ad-free push Mail account is hosted at me.com. Your inbox and mailboxes are kept up-to-date across all your iOS devices and computers.

* The App Store and iBookstore now download purchased iOS apps and books to all your devices, not just the device they were purchased on. In addition, the App Store and iBookstore now let you see your purchase history, and simply tapping the iCloud icon will download any apps and books to any iOS device (up to 10 devices) at no additional cost.

* iCloud Backup automatically and securely backs up your iOS devices to iCloud daily over Wi-Fi when you charge your iPhone, iPad or iPod touch. Backed up content includes purchased music, apps and books, Camera Roll (photos and videos), device settings and app data. If you replace your iOS device, just enter your Apple ID and password during setup and iCloud restores your new device.

* iCloud Storage seamlessly stores all documents created using iCloud Storage APIs, and automatically pushes them to all your devices. When you change a document on any device, iCloud automatically pushes the changes to all your devices. Apple's Pages, Numbers and Keynote apps already take advantage of iCloud Storage. Users get up to 5GB of free storage for their mail, documents and backup-which is more amazing since the storage for music, apps and books purchased from Apple, and the storage required by Photo Stream doesn't count towards this 5GB total. Users will be able to buy even more storage, with details announced when iCloud ships this fall.

* iCloud's innovative Photo Stream service automatically uploads the photos you take or import on any of your devices and wirelessly pushes them to all your devices and computers. So you can use your iPhone to take a dozen photos of your friends during the afternoon baseball game, and they will be ready to share with the entire group on your iPad (or even Apple TV) when you return home. Photo Stream is built into the photo apps on all iOS devices, iPhoto on Macs, and saved to the Pictures folder on a PC. To save space, the last 1,000 photos are stored on each device so they can be viewed or moved to an album to save forever. Macs and PCs will store all photos from the Photo Stream, since they have more storage. iCloud will store each photo in the cloud for 30 days, which is plenty of time to connect your devices to iCloud and automatically download the latest photos from Photo Stream via Wi-Fi.

* iTunes in the Cloud lets you download your previously purchased iTunes music to all your iOS devices at no additional cost, and new music purchases can be downloaded automatically to all your devices. In addition, music not purchased from iTunes can gain the same benefits by using iTunes Match, a service that replaces your music with a 256 kbps AAC DRM-free version if we can match it to the over 18 million songs in the iTunes Store, it makes the matched music available in minutes (instead of weeks to upload your entire music library), and uploads only the small percentage of unmatched music. iTunes Match will be available this fall for a $24.99 annual fee. Apple today is releasing a free beta version of iTunes in the Cloud, without iTunes Match, for iPhone, iPad and iPod touch users running iOS 4.3. iTunes in the Cloud will support all iPhones that iOS 5 supports this fall.

* Apple is ready to ramp iCloud in its three data centers, including the third recently completed in Maiden, NC. Apple has invested over $500 million in its Maiden data center to support the expected customer demand for the free iCloud services.

The iCloud beta and Cloud Storage APIs are available immediately to iOS and Mac Developer Program members at developer.apple.com. iCloud will be available this fall concurrent with iOS 5. Users can sign up for iCloud for free on an iPhone, iPad or iPod touch running iOS 5 or a Mac running Mac OS X Lion with a valid Apple ID. iCloud includes 5GB of free cloud storage for Mail, Document Storage and Backup. Purchased music, apps, books and Photo Stream do not count against the storage limit. iTunes Match will be available for $24.99 per year (US only).

The iTunes in the Cloud is available today in the US and requires iTunes 10.3 and iOS 4.3.3. Automatic download of apps and books is available today. Using iCloud with a PC requires Windows Vista or Windows 7; Outlook 2010 or 2007 is recommended for accessing contacts and calendars.

Initial reactions

"While it's very basic at the moment, it works pretty seamlessly and has a great interface design," said ars technica's Casey Johnston, after trying out the free beta of iTunes in the Cloud. Users can sort music by artist, song, or album, and can download songs piecemeal or in batches from iCloud. However, he points out, "Going in the other direction, there doesn't appear to be a way to get music off your device once it's on there, which you may want to do if your device is full but you'd like to pull down new music you recently downloaded. That is, unless you connect to your computer and unsync it, which kind of ruins Apple's whole no-wires aspiration." He acknowledges, "Still, this is just a beta, and the feature stands to undergo a few tweaks before it actually launches."

Apple devices

Apple is using iCloud to retain its dominance in the smartphone and tablet markets amid competition from devices powered by Google Inc. (GOOG)'s Android software.

Google's Android leads the smartphone OS market, with 5.23 million units of Android-based devices sold in the first quarter of 2011, accounting for 36 percent of the smartphone market. Apple leads the tablet market with sold 4.69 million iPads in the first quarter, for a total of about 20 million since the April 2010 debut, and more than 80% of the market. The personal computer market (desktops and laptops) are dominated by Hewlett Packard and Dell, but Apple's share in that market has grown. Apple accounted for 8.5 percent of U.S. PC shipments in the first quarter, up from 7 percent a year earlier.