Well, I'll try here.
Apache will serve files from the documentRoot directory as defined in the httpd.conf file.
Usually this is /usr/local/www
to test php, you can make a file named phpTest.php which contains the following...
Code:
<?php
php_info();
?>
and save this file in the /usr/local/www/ directory
Access this file via a browser (
http://localhost/phpTest.php) and you'll see all your php config info.
To test mysql drop down to the command line and type
$> mysql