iCloud is a storing and pushing service for IOS5 devices. iCloud services stores music, photos, apps, calendars, documents and more , wirelessly pushing them to your devices.
5GB free: When you sign up for iCloud, you get 5GB of storage free. But purchased music, apps and books, as well as your photo stream don’t count in storage, only mail, documents, camera roll, account information, settings and other app data.
Photo stream: You can take photos on one device, and it is automatically sent up to iCloud and pushed to your other devices (Mac and PC) over Wi-Fi. When new photos are pushed to your iOS device, they appear in your photo stream collection which holds up to 1000 photos. To save space on your iOS device, the photos in the stream aren’t automatically saved. You need to save them to your iOS device yourself.
You Mac and PC however, don’t need to worry about storage space, so as soon as your iOS device is within range of Wi-Fi, your photos are automatically pushed and saved to the Mac or PC’s master photo stream.
Apps: If you own more than one device, it is difficult to sync newly purchased apps. With iCloud you can now purchase an app and push it to all your iOS devices.
iWorks: If you use iWorks, Apple’s version of MS Office, you can save your documents to iCloud and access them from your iOS device. iCloud automatically saves your changes, so you’ll always be able to work on the latest version of your work, no matter which device you switch to.
Contacts, Mail and Calendar: Add or edit a contact, and it’s automatically pushed to all your other iOS devices. Every iCloud user gets a free me.com email address, and iCloud pushes new email to all your devices and keeps folders in sync. The calendar app can now sync across multiple iOS devices. Icloud and Contacts, Mail and Calendar is a serious contender to Google, which lets you sync your data across multiple devices with services like Google Contacts and Google Calendar.
Backing Up: iCloud also acts as an iOS backup service,backing your devices up daily over Wi-Fi. iCloud backs up what’s changed and not the entire system every time, making backups quicker. This is a convenient way to safeguard your data, especially for users who don’t connect their iOS devices to iTunes regularly for backups. Backups are encrypted as they are sent over the air.
iCloud backs up your purchased music, apps and books, photos and video in the Camera roll, device settings, app data, home screen and app organization, text and MMS messages and ringtones.
iTunes: iTunes in the Cloud pushes the music you purchase in iTunes to all your devices. You can also download tunes you have already purchased to any device you want.
Tunes Match: iTunes Match is an interesting service which stores your entire music collection, even songs you didn’t buy from iTunes. You don’t have to upload them, they will be automatically added to your iCloud library