http://www.appleinsider.com/articles/11/11/02/hidden_drop_box_feature_in_mac_os_x_lion_lets_you_sync_files_across_macs.html

2012-05-05 - Currently, the hidden feature lets users sync files only between Macs, as files are not pushed to iOS devices.

To enable the feature, you must activate the “Documents and Data” setting in iCloud's setting preferences. Navigating to the ~Library folder, you'll find a folder named “Mobile Documents.” (If you don't, create and save an iWork document ). You should now be able to make an alias of the “Mobile Documents” folder (or a subfolder in that folder) on your dock or Finder sidebar favorites for drag and drop syncing.

http://support.apple.com/kb/HE57