DNS / Bind - Easiest Method To Redirect A Domain To Another

I've got two domains (for sake of example, domain A and domain B). Domain A resolves correctly to my web server. Domain B is just sitting collecting dust. I didn't set these domains up, a previous programmer at my job did.

How do I configure resolv.conf, named.conf and the zone file(s) correctly to have domain B redirect to domain A?

I've already set up httpd.conf so that any requests for the host name of domain A will redirect.

e.g. [url]
I just need the DNS part of this fixed (that I'm a bit of a noob at).

Do I have to do something like this in named.conf:

Code:
zone "domaina.com" {
type master;
file "/var/named/domaina.com.hosts";
};

zone "domainb.com" {
type master;
file "/var/named/domaina.com.hosts";
};
Then in the domaina.com.hosts zone file add an alias like this?

Code:
domainb.com. IN CNAME domaina.com.

Or do I need to create a domainb.com.hosts zone file with basic info emulating domaina.com.hosts zone file, and add its entry in named.conf?