What it is: Apple's iCloud is a way to store emails, calendars, photos, music and other documents online and access them with PCs and Apple devices that have a wireless Internet connection.
Storage: Unlimited for photos, music and books; 5 gigabytes for emails and documents
Devices: iPhone, iPad, iPod Touch, Mac and PC
When: Beta versions of iCloud for iTunes without the matching function are available now for iOS 4.3.
The full system will be available this fall for mobile users with iOS 5 and Mac users with Mac OS X Lion operating systems.
How it works: Music bought through iTunes is accessible from the cloud at no cost. Songs imported from outside the Apple umbrella that can be matched to one of the 18 million songs on iTunes can be replaced — for $25 a year.
The iCloud Photo Stream service automatically uploads just-taken or imported photos and makes them accessible on multiple devices. Photos will be stored in the cloud for 30 days before being deleted; moving them to a personal folder saves them permanently.
Charging an iPhone, iPad or iPod Touch causes iCloud to back up music, apps and books purchased through Apple, as well as photos, videos and device settings.