Make URLs in plain text clickable [PHP]

<?php

/*

This fuction expects plain text with some urls to be passed to it.

It will find those URLs and make them Clickable Hyper links.
*/


function makeLinksClickable ($plaintext) 
{  

 $plaintext = eregi_replace('(((f|ht){1}tp://)[-a-zA-Z0-9@:%_+.~#?&//=]+)',  
 '<a href="\1">\1</a>', $plaintext);  
 $plaintext = eregi_replace('([[:space:]()[{}])(www.[-a-zA-Z0-9@:%_+.~#?&//=]+)',  
 '\1<a href="http://\2">\2</a>', $plaintext);  
 $plaintext = eregi_replace('([_.0-9a-z-]+@([0-9a-z][0-9a-z-]+.)+[a-z]{2,3})',  
 '<a href="mailto:\1">\1</a>', $plaintext);  
  
return $plaintext;
  
}


?>