Automatically create a link to this URL

This script will detect URLs in a string and automatically create a link to this URL.
it removes the query-string and shows only the top-level of the site linked to as text.
“autolink” makes use of the built-in PHP functions preg_replace( ). 
<?php
$txt = '
 <p>
     this is a string with
     an url in it http://fundisom.com/g5/ and
     its enough to be like that
 </p>';
 
 $txt = preg_replace('/(http|ftp)+(s)?:(\/\/)((\w|\.)+)(\/)?(\S+)?/i', '<a href="\0">\4</a>', $txt);
 
 echo $txt;
  ?>

this is a string with an url in it fundisom.com and its enough to be like that