We are using Exchange 2007 SP1 and have both Outlook 2003 SP2 (SP3 is not an option due to formatting conflicts) and Outlook 2007 SP1. All users can access and view other users calendars in the peoples calendars and Other calendars areas. However, after successfully inviting users to an appointment, only the 2007 users are able to see information in the Scheduling assistant. The scheduling tab in Outlook 2003 will remain with no information regardless of how long the appointment has been open on the users local workstation. Ive attached a picture and I think it does a much better job explaining the issue.