Target:
To host HTML or PHP files in http://serverIP/

If one want to host just htm/html files or a PHP files without MySQL database, here is what needs to be executed on the CentOS:

for HTML only
yum install httpd
for HTML+PHP
yum install httpd php
make Apache start automatically and start it:
chkconfig httpd on
service httpd start
Then add your html or php files into /var/www/html/