That depends on the php version.
Generally: If you used the installer version of PHP to install PHP then go to the download page at www.php.net and download the zip file that matches your PHP version. There are two versions available ... msi installer and a zip file, you need the zip file. If you already downloaded the zip PHP package then everything is fine
- PHP 4.3.x: the two dlls are in the dlls directory you get if you unzip the zip file
- PHP 5.x: the two dlls are in the root directory of the zip file.
Thomas