"At any time after you publish an app in the Windows Store, you can choose to add or remove a market for your app listing, or to delist it entirely.
To remove your app listing from the Store, simply de-select all the markets for it. After this is complete and submitted, you will still be able to see your app listing in the Windows Store dashboard, but it won't be visible to customers. To
list the app again, reselect the appropriate markets and resubmit. After certification, your app listing will show up again in the Windows Store."
http://blogs.msdn.com/b/windowsstore/archive/2012/06/08/listing-your-desktop-app-in-the-store.aspx
-Eric