-The iCloud Control Panel is required to use Photo Stream, Contacts and Calendars (Microsoft Outlook 2007 or later required)-

*System Requirements:
Microsoft Windows Windows Vista SP2 or Windows 7
Safari 5.1.1 or Internet Explorer 8 or later
Microsoft Outlook 2007 or 2010 recommended
Broadband Internet access

The release of iOS 5 for iPhone, iPod and iPad also saw the unveiling of Apple’s iCloud service. This online storage services can be used to synchronize photos, contacts, calendars and more between your iOS device and your Windows-based PC. Using the iCloud Control Panel you can manage your iCloud account from the Control Panel in Windows.

iCloud Control Panel

The Control Panel interface makes it possible to view at a glance how much of your available storage space you still have available as well as enabling you to control just how this space is used. if you have Microsoft Outlook installed, you will be able to synchronize your email accounts as well as contacts, calendars and tasks with the PIM.

 
How to set up iCloud
 

Download iCloud Setup