Weblabor

function get_app_token($appid, $appsecret)
{
    $args = array(
        'grant_type' => 'client_credentials',
        'client_id' => $appid,
        'client_secret' => $appsecret
    );

    $ch = curl_init();
    $url = 'https://graph.facebook.com/oauth/access_token';
    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_HEADER, false);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch, CURLOPT_POST, true);
    curl_setopt($ch, CURLOPT_POSTFIELDS, $args);
    $data = curl_exec($ch);

    return str_replace('access_token=', '', $data);
}

$facebook = new Facebook(array(
   'appId' => $appId,
   'secret' => $secret,
   'cookie' => false
));

$token = get_app_token($appId, $secret);


$facebook->api("/{$pageId}/feed", "post", array(
   'message' => "First message",
   'access_token' => $token
));