yum --disableplugin=fastestmirror install php-devel libmcrypt-devel gcc
cd /tmp
wget http://museum.php.net/php5/php-5.3.3.tar.gz
tar xf php-5.3.3.tar.gz
cd php-5.3.3/ext/mcrypt/
phpize
aclocal
./configure
make
make install
Remove extension=mcrypt.dll
vi /etc/php.ini
Restart Apache
service httpd restart