How can I set PHP5 as default?

[ktsirig]

Hello all,
on the server machine I am working, there is for some unexplained reason both PHP4 and PHP5 installed. Actually, for PHP4, there is only the PHP4-core files as I saw in the administration panel. However, I have a script that has shown some errors when being executed via PHP4 but works ok when PHP5 takes over. My question is, is there a way to "tell" Apache that I want to use only PHP4? The weird thing is that there's only the php5_apache2 module installed, but when I write in a terminal :

 php -v 

,
I get:

PHP 4.3.10 (cli) (built: Apr 23 2005 04:10:27)
Copyright (c) 1997-2004 The PHP Group
Zend Engine v1.3.0, Copyright (c) 1998-2004 Zend Technologies

and also, when I ran:

which php

,
I get:

/usr/bin/php

but I can see that there is also

/usr/bin/php5

there. And if I write:

php5 -v

, I get:

PHP 5.0.3 (cgi) (built: Apr 23 2005 08:18:44)
Copyright (c) 1997-2004 The PHP Group
Zend Engine v2.0.3, Copyright (c) 1998-2004 Zend Technologies

Is there something in the Apache configuration file that I must change so that Apache will use Php5 only?

Thank you!