Dont listen to vigol he is completely wrong. cgi-bin is for CGI scripts and NOT PHP.
PHP will be parsed by the webserver as long as you tell it WHERE the php files are and add support for the extension. You can put your PHP files in your web directory root aka /var/www/htdocs or whatever it is.
ronald-be can you be more specific. What are you trying to do? Do you get empty pages when you point your browser to http://localhost
or are they blank when you are trying to use PHP?