http://sms.example.com/public/http/?user=andrey&pass=andrey123&action=post_sms&target=71234567890&sender=andrey-win&message=privet
http://s1.example.com/sys/send.php?login=andrey&psw=andrey123&sender=andrey-win&phones=71234567890&mes=privet
<?php
$login=$_POST['user'];
$psw=$_POST['pass'];
$phones=$_POST['target'];
$mes=$_POST['message'];
$sender=$_POST['sender'];
print file_get_contents('http://s1.example.com/sys/send.php?charset=utf-8&login=' . $login . '&psw=' . $psw . '&phones=' . $phones . '&mes=' . $mes . '&sender=' . $sender . '"');
?>