[CentOS] centos firewall?

Hi,

>> How do I add 5900 to the centos firewall? How do I edit the conf
>> file?

>> Learn how to add ports to your iptables file, then it should work.

OK, maybe I should have been more clear and stated that I am following:

http://www.centos.org/docs/5/html/Deployment_Guide-en-US/ch-fw.html

and looking for /etc/sysconfig/iptables or /etc/sysconfig/system- 
config-selinux

and not finding it....

-Jason