here's the real deal:
http://us4.php.net/include/
and here's the quickie:
PHP Code:
<?php include 'http://www.example.com/file.php?foo=1&bar=2'; ?>
or
PHP Code:
<?php include 'file.php?foo=1&bar=2'; ?>
or
PHP Code:
<?php include '/sub/file.php?foo=1&bar=2'; ?>