Para formatar nomes em pt-br:
<?php
 function titleCase($string, $delimiters = array(" ", "-", ".", "'", "O'", "Mc"), $exceptions = array("de", "da", "dos", "das", "do", "I", "II", "III", "IV", "V", "VI"))
 {
 /*
 * Exceptions in lower case are words you don't want converted
 * Exceptions all in upper case are any words you don't want converted to title case
 * but should be converted to upper case, e.g.:
 * king henry viii or king henry Viii should be King Henry VIII
 */
 $string = mb_convert_case($string, MB_CASE_TITLE, "UTF-8");
 foreach ($delimiters as $dlnr => $delimiter) {
 $words = explode($delimiter, $string);
 $newwords = array();
 foreach ($words as $wordnr => $word) {
 if (in_array(mb_strtoupper($word, "UTF-8"), $exceptions)) {
 // check exceptions list for any words that should be in upper case
 $word = mb_strtoupper($word, "UTF-8");
 } elseif (in_array(mb_strtolower($word, "UTF-8"), $exceptions)) {
 // check exceptions list for any words that should be in upper case
 $word = mb_strtolower($word, "UTF-8");
 } elseif (!in_array($word, $exceptions)) {
 // convert to uppercase (non-utf8 only)
 $word = ucfirst($word);
 }
 array_push($newwords, $word);
 }
 $string = join($delimiter, $newwords);
 }//foreach
 return $string;
 }
?>

Usage:
<?php
 $s = 'SÃO JOÃO DOS SANTOS';
 $v = titleCase($s); // 'São João dos Santos' 
?>