preg_grep with the case insensitivity flag “i "kullanın:

$result = preg_grep('/pattern/i', $array);

strcasecmp fonksiyonu kullanarak bu deneyin:

$array = array('foo', 'bar', 'baz', 'quux');
$needle = 'FOO';

$hit = false;
foreach ($array as $elem) {
    if (is_string($elem) && strcasecmp($needle, $elem) == 0) {
        $hit = true;
        break;
    }
}
var_dump($hit);

Ben strtolower sadece yolu vardır bildiğiniz gibi. Ayrıca PHP doc Yorum bakınız: http://ch2.php.net/manual/en/function.in-array.php#88554

Edit: As you can see in the comment, there is of course more than one way to solve it. I probably miss spelled what I tried to say ;-). Sorry.