If you would like to fetch the data from an external link you want to get the page using curl.
Here's an example
<?php
$ch = curl_init("http://www.google.nl");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
$result = curl_exec($ch);
curl_close($ch);
$title = preg_match('!<title>(.*?)</title>!i', $result, $matches) ? $matches[1] : 'No title found';
$description = preg_match('!<meta name="description" content="(.*?)">!i', $result, $matches) ? $matches[1] : 'No meta description found';
$keywords = preg_match('!<meta name="keywords" content="(.*?)">!i', $result, $matches) ? $matches[1] : 'No meta keywords found';
echo $title . '<br>';
echo $description . '<br>';
echo $keywords . '<br>';
?>
For google.nl this returns:
Google
No meta description found
No meta keywords found
The meta description and keywords might need more tweaking for your use.
Little sidenote cURL is not installed by default in apache so you might need to install if first.
Here's the cURL php function page: http://nl3.php.net/manual/en/ref.curl.php