Once you have completed installation and configuration the Apache, PHP and MySQL in Linux system.

If you have gotten below warning message when you starting the Apache web-server.

/etc/init.d/httpd restart

starting httpd: [Wed Feb 06 00:20:44 2013] [warn] module php5_module is already loaded, skipping
You have two of the lines in your httpd.conf: LoadModule php5_module /usr/lib/apache/libphp5.so

May be the LoadModule configured two of the lines in httpd.conf and conf.d/php.conf, to check in both configuration file and remove that line  from any one of the files

For example:
<IfModule prefork.c>
  LoadModule php5_module modules/libphp5.so
<IfModule worker.c>

Finally, restart the Apache server
# /etc/init.d/httpd restart