Global Calendar

Hi all :
I will be rolling Citrix XPa and NFuse Classic soon in my Health organization and I need some help,We have 5 conference rooms in my Organization I?m Looking for a Calendaring Software to setup a Global Calendar for Events and Booking thoseConference rooms in my Health Services organization where user can book conference room locate in the organization and also check events and Synchronize them with Outlook 2000 and higher . Btw any solution can work beside Outlook 2000 Team Calendar 2.0 🙂