Can't see attendee calendar when planning a meeting

[HD101]

When planning a meeting some of our users can't get any information about other peoples calendar when inviting them to attend the meeting, while others can. Some are using Outlook 2000 and others 2003, doesn't seem to matter. Some are on NT and others are on 2000 or XP.
One user can see the information when on his computer, but when he logs on to a new computer with Outlook just installed, he can't see the information.
Is there a setting on the client side that determines if they get calendar information when planning a meeting?

 

[sawedoff]

Users can keep you from viewing their Free/busy details by going to Tools > Options > Calendar Options, Free busy options and removing the publish on the server time. But this wil only keep you from viewing that user's info, not all users.

Also, XP allows more info to be viewed, but also allows the info to be blocked for individual appointments.

Sawedoff