This stumped me for a while as I needed PDO MYSQL for the excellent Zend Framework. You won't find PDO MySQL in easyapache as CPanel don't officially support it yet. I was, however, able to install it by compiling PHP manually. To do this you'll need to first install the latest PDO and PDO_MYSQL drivers which you can do with the following commands:
pecl install pdo
pecl install pdo_mysql
You then need to compile PHP manually with something similar to the following command lines:
service httpd stop
cd php-5.2.1 (or whatever is your latest install)
./configure --with-apxs=/usr/local/apache/bin/apxs --prefix=/usr/local --with-xml --enable-bcmath --enable-calendar --with-curl --enable-exif --enable-ftp --with-gd --with-jpeg-dir=/usr/local --with-png-dir=/usr --with-xpm-dir=/usr/X11R6 --enable-magic-quotes --with-mysqli --with-mysql=/usr --with-openssl --enable-discard-path --with-pspell --enable-sockets --enable-track-vars --with-ttf --with-freetype-dir=/usr --enable-gd-native-ttf --enable-soap --with-zlib --enable-pdo=shared --with-pdo-mysql=shared --with-pdo-sqlite=shared --with-sqlite=shared
service httpd restart
Make sure you get a copy of your existing configure line before issuing these commands and then add "--with-zlib --enable-pdo=shared --with-pdo-mysql=shared --with-pdo-sqlite=shared --with-sqlite=shared" to the end of it.
You'll then need to update the php.ini file with:
[You can find the location of your php.ini file and your existing compile options by running a PHP script that simply calls the phpinfo() function.
Don't forget to restart apache again after updating the php.ini file with:
Hope that helps.