iCloud is a service platform that supersedes MobileMe.

Features:

• Daily backups of iOS device to iCloud over Wi-Fi.
  Purchased music, apps & books.
  Camera roll
  Device settings
  App data
• Documents in the cloud,
• Automatically syncs between iOS devices and computers (Mac and Windows)
• Download all already purchased songs from iTunes with no additional fee.
• iCloud comes free with iOS 5
• Free 5GB of storage for mail. Apps and books do not count. Photo Stream does not count.