Microsoft Entourage 2004 and auto-booking resources
Microsoft Entourage 2004, by itself, does not currently support auto-booking of resources (like conference rooms or computer projectors or other items that it is convenient to share and schedule).
Therefore, if you intend to reserve a resource, you should contact the person responsible for it and make sure it really is reserved. Do not make assumptions. The resource is not reserved until the event invitation you send from Entourage is accepted into that resource's calendar, and that will probably require manual intervention by the person who maintains that resource's calendar.
We currently advise that anyone responsible for a resource account check its inbox and calendar on a regular basis to watch for new events proposed by people who have invited the resource. Inviting the resource is slightly different than auto-booking, and that could happen even from programs that support auto-booking.