A user of OWA (outlook web access) cannot create an event on a public shared calendar and invite attendees, the invite \ button is grayed out. This is by Microsoft design (google it).
In order to allow an OWA user to create a calendar event with his calendar, other users calendar, and a public calendar, \ the public calendar must be assigned an email address and the OWA user must create the event from his own personal \ calendar, then click invite, then search for the public calendar as an attendee. When he saves the event, it will \ be saved on his personal calendar, the public calendar, and any other user attendees he has selected.
For dynatron, I setup a 'Conference Calender' and a 'Impl & Trng Calendar' public calendars. Note, to get email \ working as a resource for these calendars you do NOT have to create an Active Directory user and an exchange mailbox. \ These public calendar emails will not even use an exchange mailbox, just the address. So no AD editing needed. \
Just open the exchange System Manager on your exchange server. Expand 'Administrative Groups'->'first administrative group'-> \ 'Folders'->'Public Folders'. Properties on your public calendar folder name. E-mail Address tab. Add theemail@domain.com \ SMTP. Goto Exchange Advanced tab, uncheck the 'Hide from Exchange address lists' box (this way it shows up in your \ outlooks Global Address List). And thats it.
If you wanted a calendar as a true resource, to deny duplicate bookings etc... you cannot do it with a public \ calendar. In order to do this, the calendar has to be owned by a regular AD user with a regular exchange mailbox. \ See http://www.slipstick.com/calendar/skedresource.asp So you would setup an AD user, then login to outlook as that \ user, goto Tools->Options->Preferences Tab->Calendar Options->Resource Scheduling and check the first 2 or whatever \ checkboxes. Then delegate users to manage this calendar and allow others to view/edit etc...
Doing this user calendar instead of a public calendar will also allow others booking an event to see the calendars \ free/busy information (cannot see free/busy info of a public calendar http://support.microsoft.com/kb/260724)
calendar/mail/contact... Just open outlook as admin, or one who has admin access, and right click public folder, create, then select the correct \ 'Folder Contains'. Then if you want it as a resource like above, goto exchange System Manager and goto properties on \ the new public folder item...