adding cusom ads

[stable2]

I've written a PHP script that I'm using in part of my site that works perfectly well and I'd like to ad this to the forum. The script is basic and will rotate ads - from what I've seen of the new ad manager in vb4, you can't get ads to rotate that easily.

I'd like to include this script in the header, is there a way to simply get vb to load something like
<?php include 'path/to/file.php'; ?> for all templates?

Or I am approaching this in the wrong way?