String to URL generator - impoved

function tourl($strText) {
    $strText = preg_replace('/ã|â|á|ä|à/i','a',$strText);
    $strText = preg_replace('/ê|é|ë|è/i','e',$strText);
    $strText = preg_replace('/î|í|ï|ì/i','i',$strText);
    $strText = preg_replace('/õ|ô|ó|ö|ò/i','o',$strText);
    $strText = preg_replace('/û|ú|ü|ù/i','u',$strText);
    $strText = str_ireplace(array('ç','ñ'),array('c','n'),$strText);
    $strText = preg_replace('/[^A-Za-z0-9-]/', ' ', $strText);
    $strText = preg_replace('/ +/', ' ', $strText);
    $strText = trim($strText);
    $strText = str_replace(' ', '-', $strText);
    $strText = preg_replace('/-+/', '-', $strText);
    $strText = strtolower($strText);
    return $strText;
}