Setting up an internal caching dns server with internal web server

I am trying to setup an internal dns server for my network. I am
hosting websites for several domains on two different FC3 boxes with
each box assigned an IP address on my local area network. I perform
port forwarding of 80 traffic to one web server and port 8080 traffic
to another server via my sonicwall firewall which has my external ip
address. I have a third box hosting email for one of these 6 domains.
All public dns resolution currently is handled by public dns servers
and I wish to maintain this.

I would like to setup a caching name server that will resolve the
internal network ip addresses when I query th web addresses for the 6
domains or send and retrieve email via my internal network mail server
(143,25 and 110 traffic is port forwarded to the mail server from the
outside). Essentially I need to setup the nameserver as a simple
caching name server with the addition of A records for each of the
server addresses that I am hosting in the 6 different domains without
this dns server becoming the authorative name server for each domain so
as not to break the mail server's lookup of mx records for mail sent to
users in the domains for whom I am hosting the websites.

I hope I explained this clearly enough. I am setting up my dns via
webmin on my fc3 box, so any help using that tool would also be
helpful. I will quicky respond to any requests for my information
should by description of my problem need clarification.

Skydiver