OM1

$params = array(
        'client_id' => $client_id,
        'client_secret' => $client_secret,
        'code' => $_GET['code'],
        'redirect_uri' => $redirect_uri
    );

$token = json_decode(file_get_contents('https://oauth.vk.com/access_token' . '?' . urldecode(http_build_query($params))), true);

$token['access_token']