@Burti; PHP tarafında POST isteği göndermenin binbir türlü yolu var.

#1: file_get_contents:

<?php

	$data = http_build_query(array('username' => 'saintx', 'password' => '123456789'));

	$options = array('http' => array('method' => 'POST', 'header' => 'Content-Type: application/x-www-form-urlencoded', 'content' => $data));

	$context = stream_context_create($options);

	$url = 'https://www.facebook.com/login.php';

	$response = file_get_contents($url, false, $context);

	// print_r($response); /* {"status":true} */

	$result = json_decode($response);

	if ($result->status !== false)
	{
		// echo "Başarıyla giriş yapıldı.";
	}

#2 cURL:

<?php

	$data = array('username' => 'saintx', 'password' => '123456789');

	$url = 'https://www.facebook.com/login.php';

	$handle = curl_init();

	curl_setopt_array(array(
		CURLOPT_URL => $url,
		CURLOPT_BINARYTRANSFER => true,
		CURLOPT_RETURNTRANSFER => true,
		CURLOPT_NOBODY => true,
		CURLOPT_HEADER => false,
		CURLOPT_POST => true,
		CURLOPT_POSTFIELDS => true,
	));

	$response = curl_exec($handle);

	curl_close($handle);

	// print_r($response); /* {"status":true} */

	$result = json_decode($response);

	if ($result->status !== false)
	{
		// echo "Başarıyla giriş yapıldı.";
	}

#3 fsockopen:

<?php

	$useragent = 'Mozilla/5.0 (Windows NT 6.1; WOW64; rv:31.0) Gecko/20100101 Firefox/31.0';

	$data = 'username=saintx&password=123456789';

	$host = 'www.facebook.com';

	$port = 443;

	$timeout = 15;

	$handle = fsockopen($host, $port, $errno, $errstr, $timeout);

	$request = "POST /login.php HTTP/1.1\r\n";
	$request .= "Host: {$host}\r\n";
	$request .= "User-Agent: {$useragent}\r\n";
	$request .= "Content-Type: application/x-www-form-urlencoded\r\n";
	$request .= "Content-Length: " . strlen($data) . "\r\n";
	$request .= "Connection: close\r\n\r\n";
	$request .= $data . "\r\n\r\n";

	fwrite($handle, $request);

	$response = "";

	while ( ! feof($handle))
	{
		$response .= fgets($handle, 4096);
	}

	fclose($handle);

	// print_r($response); /* {"status":true} */

	$result = json_decode($response);

	if ($result->status !== false)
	{
		// echo "Başarıyla giriş yapıldı.";
	}

Burada en kolay yol cURL kullanmak oluyor tabi ki de hangisini kullanman gerektiğine sen karar vereceksin.