Install php:
1. download the tar from www.php.net
2. ./configure --with-apxs2=/home/www/apache-2.2.4/bin/apxs --with-mysql
3. make
4. make test
5. make install
6. add the following lines in httpd.conf in apache configuration:
LoadModule php5_module modules/libphp5.so
AddType application/x-httpd-php .php .phtml
7. restart apache