samba - Mar 2002 - How do I setup Samba Shares?

I am trying to setup a Samba share that does the following:

1) Allows guest users access to first level directory
2) Allows only specified users to subdirectories of the above first level
directory.  Guest users are not allowed, unless specifically noted.

What do I need to do to get the above scenario working?

Thanks.
Kevin Bramblett
IT Admin
DSS Research