See http://www.slipstick.com/calendar/scheduleall.htm for ways to do this.

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Sue Mosher, Outlook MVP
Author of Microsoft Outlook 2007 Programming:
Jumpstart for Power Users and Administrators
http://www.outlookcode.com/article.aspx?id=54
>I need to set up a monthly calendar for my entire office that will show who
> is in and out of the office. I need for this to be able to be viewed by all
> (obviously) and that everyone can get in themselves and input or change their
> information.