Features
Custom Integrations
FREE BUSY STATUS In In Outlook.
Supported through MAPI Connector using Scheduling TAB of Outlook.
Using scheduling tab in Outlook and refreshing Free /Busy status menu item, once can check the free/busy status of any attendee provided the attendee has allowed seeing Free/Busy status from MAPI Connector (Outlook) profile though Manage Global permissions or has set the same from the AJAX WEBMAIL interface.
So once a meeting is being scheduled and all attendees have been added then before sending saving one can check the Free Busy status of all attendees for by doing following:
Click Options > Refresh Free/Busy at the bottom of the interface. The screenshot with refreshed data will be shown as shown in the Fig 1 (Please note that this will work only if attendees have allowed seeing their free /busy status and user is on MAPI Connector profile while working from Outlook.):

Figure1: Checking Free/Busy status of attendees while scheduling meeting from Outlook Connector Profile.
Free/Busy status in WEBMAIL interface
Free/Busy status is also available in WEBMAIL. Currently the
Tasks/Calendars/Notes and Journals are only viewable in Non AJAX Interface. Q3
2010 release will have everything moved to AJAX Interface which currently only
handles mail and contacts. The free busy status in webmail is depicted as shown
in Fig 2

Fig 2: Free/Busy status in WEBMAIL Interface.
Outlook Connector Screen Shots

Ajax Interface
Screen Shots