[Zope] Accessing ZClass data

[Montagne, Michael]

Newbie question alert!!

I have created Zclasses to represent my users using ZUserfolder.  Each one
has a property sheet called UserData with a StaffID property.  I also have a
property sheet called OfficeStatus that will contain info about office
status (no kidding).  I don't understand how to access an instance of this
ZClass by referencing it's StaffID.  All the users exist in the acl_users
folder, but how do I reference them to manipulate the properties?  Can I
search by any property?
I'm a bit stuck.

-thanks,
mjm