I have installed CentOS-6 server in our DMZ.
I have a public IP address which I will use for it.
Now, how should I set up its DNS in order to make it accessible from internet?
Is there any particular steps required for BIND in order to propagate the server to internet?
No you don't have to set up bind on your server to make it accessible from internet. If you have public IP then your server is already accessible from all over the world (of course only for people who knows your server IP).
What you have to do to make your server accessible via domain name is register your domain in one of domain operators and set up proper DNS record for your server .
Yes you can set up BIND and setup this record on your own DNS server ...but you should have at least two DNS servers.