When sharing calendars, it would be nice - and could be all the ressource management a business like ours needs - to display on what tasks or projects someone is working. I made a quick mock-up (sorry it was not available for the last week):

These bars would represent the availability and workload. All sort of meaning could be attached to the outline and fill colors (like if the border color is attached to a ressource, we could view a lot of ressource's calendars and be able to understand what is shown). On Mouse-Over, details would be shown on which projects / tasks the ressource is working on. When viewing several calendars one would be able to grasp instantly how the business is going, who is over/under utilized, etc. I also like the tiny clocks � la Outlook to show an appointment's time in month view.