#download the source
#curl -L -o /tmp/php.tar.gz http://www.php.net/get/php-5.2.0.tar.gz/from/this/mirror

#uncompress the file
#cd /tmp
#tar xvzf php.tar.gz

#configure, make and make install
#cd /tmp/php-5.2.0
#./configure --prefix=/usr/local/php-5.2.0 --with-apxs2=/usr/local/httpd/bin/apxs --with-mysql=/usr/local/mysql
#make
#sudo make install

#create a link
cd /usr/local
sudo ln -s php-5.2.0 php

#cleanup
rm -fr /tmp/php*