Domain Name and Web Sites

I have an intranet in a W2K Domain named “xyz.com” and “xyz.com” is registered on the internet.
I have a web site on the internet named xyz.com. I want my users to be able to access the external web site. DNS1 points to my intranet and DNS2 and DNS3 points to the internet.

Users cannot access the external xyz.com site do they need to use xyz.com:8080

I know if I put the external DNS’s first I have trouble setting up machine domain accounts.

In a Nut shell how do you configure a W2K domain with intranet and internet domain names the same.