Please help me set up DNS/Bind 9

[Ben Abrams]

I have a fresh install of Red Hat ES 4.0 and want to set up DNS to use internally.  We have a NAT-ed network with a single outside IP address.  We do email internally for about 70 users.  I want the machines within our network to query our internal DNS for the resolution of machines internally with internal addresses (192.168.2.xxx), but then use our ISP's DNS for resolution of anything outside our network.  There would not be any outside queries to our DNS server.  Bind 9 is installed, but I'm very confused as to how to set it up to do what I want it to - and which files to change.  Please forgive my misuse of any DNS lingo.  Also, what type of DNS server do I need in this setup...master? slave?
Thanks for any help!!!

Ben Abrams
LRS Architects, Inc.
Portland, OR