Not something I use, but this tutorial at HowtoForge might be something for you.
Read it here
This tutorial shows you how to configure BIND9 DNS server to serve an internal network and an external network at the same time with different set of information. To accomplish that goal, a new feature of BIND9 called view is used. As a tutorial it'll walk you through the whole set up, but initial knowledge of BIND and DNS is required, there are plenty of documents that cover that information on the Internet.