"Linkifying" URLs in twitter feed

  function convertURLsToLinks ( $toConvert )
  {
    
    $toConvert = preg_replace("{([^\'\"\>]){1}(http://|www\.)+([\w\.\/]*)}is", " <a href=\"http://$3\" target=\"_blank\">http://$3</a>", $toConvert);
    $toConvert = preg_replace("{([\'\"\>]){1}(http://|www\.)+([\w\.]*)([\'\"\<]){1}}is", " $1http://$3/$4", $toConvert);
    $toConvert = preg_replace("{([^\'\"\>]){1}([\w\.]+)(@)([\w\.]+)}is", " <a href=\"mailto:$2$3$4\" target=\"_blank\">$2$3$4</a>", $toConvert);
    $toConvert = preg_replace("(@([a-zA-Z0-9]+))", "<a href=\"http://www.twitter.com/\\1\" target=\"_blank\">\\0</a>", $toConvert);
    return $toConvert;
    
  }