Users of the new iTunes 11 who also happen to own an iCloud account will be able to see all their stuff in the iTunes library, even if the content was never stored on the computer to begin with.A customer’s music, movie, and TV show purchases in iCloud now appear inside the iTunes 11 library. Which means you can just sign in with your Apple ID and gain instant access to everything.
You can either double-click the song / movie to play it directly from iCloud, or download a copy that you can then sync to a device or play offline (as shown in the image above, courtesy of the Cupertino giant).
This is just one of the many features inside iTunes 11, available as a free download for Mac and Windows (links below).
Download iTunes 11 for Mac
Download iTunes 11 for Windows