Customizing Your iCloud Experience
When running iOS 5, from your iPhone or iPad's Settings app, tap the iCloud option displayed on the left side of the screen (under the Settings heading) to access the menus associated with customizing how your iOS device will utilize iCloud.
From the iCloud screen within Settings, you can choose the email addresses that will be associated with your iCloud account or set up a free [username]@me.com email account. Below the email account option, you'll see a list of all iCloud-compatible apps currently stored on your iOS device, such as Mail, Contacts, Calendars, Reminders, (Safari) Bookmarks, Notes, Photo Stream, and Find My iPad/Find My iPhone.
In conjunction with each app listed is a virtual on/off switch that allows you to determine which apps will automatically work with iCloud for syncing and backing up data. Tap the Storage & Backup option to see how you're currently utilizing your allocated online storage space, managing your storage space, and/or purchasing additional online storage space.
At the bottom of the Storage & Backup screen is the option to turn on/off the Back Up to iCloud feature, which can replace the need to manually back up your iPhone or iPad using the iTunes sync process (which requires connecting the device to your primary computer using the supplied USB cable).