iCloud includes push email, calendaring, and contact services. That means whenever you get an email, it's immediately made available on all your devices. Whenever you make or change an appointment it shows up in your calendar on all your devices. Whenever you add or change contact information, its reflected in the contacts on all of your devices. You can access these services via the Mail, Contacts, and Calendar apps on your iPhone, iPod touch, or iPad, via the iCloud.com website from any desktop browser, or through popular mail, calendar, and contacts apps on your Mac or Windows PC.
iCloud will also sync Bookmarks, Notes, and Reminders.
If you didn't originally set up your iPhone, iPod touch, or iPad with iCloud, or if you want to use a different iCloud account for Mail, Contacts, and Calendars than you do for iTunes purchases, for example, or you simply want to add an additional account to your device, here's how to get it working.
Whether you're setting up iCloud on your iPhone, iPod touch, or iPad for the first time and want to choose which services are turned on and which are turned off, or you've already set it up but want to make some changes, it's easy to configure.
You can selectively choose to enable or disable Mail, Contacts, Calendars, Reminders, Bookmarks, Notes, Photo Stream, Documents in the Cloud, and Find my iPhone/iPod/iPad.
Turning off an iCloud feature on your iPhone, iPod touch, or iPad will remove the associated data from your device, but not from iCloud's servers. So, if you change your mind again, just repeat the process and flip the switch back on.
You can access iCloud Mail, Contacts, and Calendars, as well as Documents in the Cloud, and Find my iPhone/iPod/iPad from any Mac, Windows, Linux, Unix, or other PC with a modern web browser via:
To access your iCloud data via a Microsoft Windows PC, first you need the iCloud Control Panel for Windows Vista SP 2 or Windows 7.
You can choose to turn on Mail, Contacts, Calendars & Tasks (Reminders), Bookmarks, and Photo Stream. The following software will then be able to access iCloud data:
iCloud is built into Apple's OS X 10.7 Lion for Mac, and will be even better integrated into the upcoming OS X 10.8 Mountain Lion.
You can choose to turn on Mail, Contacts, Calendars, Bookmarks, Photo Stream, Documents in the Cloud, Back to my Mac, and Find my Mac. The following software will then be able to access iCloud data.
If you want to access your iCloud mail from a non-iOS, Windows, or Mac mail program, or with an alternate smartphone platform like BlackBerry, Android, Windows Phone, etc. you'll need to set it up manually using IMAP and SMTP.
Note: Apple advises that, if you receive errors using SSL, you try using TLS instead.
If you still need help with mail, contacts, or calendars on your iPhone, iPod touch, or iPad, or any other iCloud feature, head on over to our iCloud Forum and ask away!
Ally Kazmucha, Chris Oldroyd, and Gary Mazo contributed major sections of this guide.