how to view all calendars without having to give permission?

You can use the PFDavAdmin tool to do this.  The user who is running this tool has to have administrative-level permissions in Exchange:

http://www.microsoft.com/download/en/details.aspx?DisplayLang=en&id=22427

This article has some specific instructions on how to use the tool for calendar permissions:

http://social.technet.microsoft.com/Forums/en-US/exchangesvradmin/thread/dff4d2f4-da03-42db-81b5-7d113d2d5ded

when the chane is made does it take time for it to propegate through or should it be an immediate update when the user is added with reviewer rights?

This can be done quickly and easily using delegate access.

Simply add the executive Admin as a Delegate to the Users Outlook Profile
Set her permissions on the Calendar
 
If she need to only view it set her to reviewer

If she needs more, you can set to Author or Editor

apache09,

Yes I am aware of that method but I need a way to do it from the server so I dont have to go into everyones account and set her as the delegate.

Is there a place in MS Exchange to set that so it will propegate down to all users and she can just open each one without my intervention needed?

Hi sbodnar
I have a silly question: already the admin should easily be able to view everyone's availabilty by design. Does this person also need to see the details and/or make edits to these calendars??

tell me more
kfalandays

Hi apache09, no need to add to exchange admin group, simply use group calendars to view availability. That is why I asked if admin needs to see actual details
kfalandays