You can from the Apple.com support site. The roughly 40MB utility installs as an option in the Windows Control Panel--just click Start, Control Panel, iCloud to access the tool and manage your iCloud account, as well as what information is synced between iCloud and your Windows PC or Microsoft Outlook software.
There are five checkboxes available that let you choose to sync email, contacts, and calendar items with Outlook, and keep your browser bookmarks and iCloud Photo Stream synced. Below the checkboxes is a display indicating how much iCloud storage space you're using along with a button to manage it. At the very bottom is a checkbox to add the iCloud tool to the Systray at the bottom right of Windows for easier access.
Checking the Mail, Contacts, or Calendars & Tasks checkboxes adds iCloud as an additional account in Outlook. Mail doesn't seem to actually sync with any of my existing accounts in Outlook. Instead it adds the iCloud email account to Outlook. But, I already have my own domains and established email addresses, so I have no intention of using the iCloud account. I guess that means my email won't be synced between devices, or with Outlook.
With a little cleanup to weed out any duplicates the contacts and calendar added to Outlook work fine. I can add a new contact on my iPad, or for me from my iPhone, and those updates will automatically populate to Outlook after a few minutes. There is also a button on the ribbon at the top to manually refresh from iCloud if need be.
The Bookmarks and Photo Stream checkboxes each includes an "Options..." button. For Bookmarks, the only option is whether to sync bookmarks from Internet Explorer or Safari--sorry Firefox and Chrome users. The Photo Stream options let you choose the folder locations where you want iCloud to store files it downloads from Photo Stream, and where you want iCloud to automatically upload from to share pictures with your other iCloud-connected devices.
The iCloud Storage section lets you see at a glance how much space you are currently using, and how much is still available. You can click the "Manage" button to get more details and either free up or purchase more space.
I have my iPhone 4S, iPad, and iPad 2 all . Combined, the three backups are using up 2.3GB of the 5GB Apple provides for free. I can see how much space each backup is using, and delete any of the backups if I'd like to free up some space. You can also see how much space email is using--which for me is negligible since I'm not using it.
There is a button to "Buy More Storage..." at the upper right. You can get an additional 10GB for $20 per year, 20GB for $40 per year, or 50GB for $100 per year. While not entirely apples to apples (pun intended), though, you can get for a limited time from Box.net.
There's --like allowing me to sync my own email account across iCloud instead of just the silly "me.com" account. But, I appreciate knowing that new calendar events, contact items, and pictures are kept in sync between my iPhone, iPad, and Windows PC. The moment I snap a picture with my iPhone 4S or iPad 2, it is automatically uploaded to Photo Stream and synced with my other devices. Even if my device gets lost or stolen, I will still have those photo memories.
If you haven't on your Windows PC, and get started.