Are your resources configured per this web page?
http://www.slipstick.com/calendar/skedresource.htm#ol2000

Signature
Milly Staples [MVP - Outlook]
Post all replies to the group to keep the discussion intact. Due to
the (insert latest virus name here) virus, all mail sent to my personal
account will be deleted without reading.
After furious head scratching, rmcole asked:
| We are on an exchange server and have several resources set up by our
| IT department. However, when anyone (with permissions) attempts to
| schedule a resource, we cannot see it on the resource's calendar,
| causing users to schedule the same resource at the same time for a
| different meeting..