looking for….

I am a newbie. I am trying to setup a feature like below with wordpress. Google search really got me confused.

I wish to have a calendar (like livecalendar without total page refresh) wherein it incorporates multi-author event posts. The events postings (even future dates) should be in a separate URL not visible to public and only accessible to authorized users for posting events. In addition, calendar should display a summary of events below the calendar if clicked on a particular date.

Is this possible?
are there any plugins for this?

PLease help me out.

Thanks,

drb