How to sync all your documents in iCloud

Between computers ONLY.

Have "Documents & Data" syncing turned on all your computers ( iCloud System Preferences Panel).

You need to create a folder to hold all of your documents and create access to that folder through the Finder Sidebar. 

Let's begin:

• While the drop down menu is visible, press and hold the option key (alt) which will reveal the hidden "Library" option.
• Select the "Library" option from the list and the contents of the Library folder will be displayed in the Finder.
• Locate and open the "Mobile Documents" folder.
• Create a new folder inside the "Mobile Documents" folder, name it appropriately (e.g. "My iCloud").
• Make a alias and drag the new folder to the "Favorites" section of the Finder Sidebar.
• Repeat steps 1 through 6 (with the exception of step 5) on each computer.

You can now add files and folders to the folder in the sidebar and they will sync between your computers. You can not currently access this folder from an iPad, iPhone, iPod or iCloud.com.

Thanks to Apple and Winston Churchill for the tips