POST /index.php HTTP/1.1
User-Agent: Opera/10.00 (Windows NT 6.0; U; en) Presto/2.2.0
Host: test2.ru
Accept: text/html, application/xml;q=0.9, application/xhtml+xml, image/png, image/jpeg, image/gif, image/x-xbitmap, */*
Accept-Language: ru-RU,ru;q=0.9,en
Accept-Charset: iso-8859-1, utf-8, utf-16, *
Accept-Encoding: deflate, gzip, x-gzip, identity, *
Referer: http://test2.ru/
Proxy-Connection: Keep-Alive
Content-Type: application/x-www-form-urlencoded
Content-Length: 74
referer=%2F&action=dologin&username=123&password=123

#include "stdafx.h"
#include "winsock2.h"
#include <stdio.h>
#include <fstream>
#include <string.h>
#pragma comment(lib, "WSOCK32.lib")

using namespace std;

//функция вывода ответа сервера в файл
int recvtofile(char recvbuf[99999])
{
	ofstream outfile;
	outfile.open("recv_log.txt");
	outfile.write(recvbuf,strlen(recvbuf));
	return 0;
}

int _tmain(int argc, _TCHAR* argv[])
{
    WSADATA wsaData;

    if(WSAStartup(MAKEWORD(2,2), &wsaData) != NO_ERROR)
    {
        printf("Error at WSAStartup()\n");

        getchar();
        return 0;
    }

    SOCKET ConnectSocket;

    ConnectSocket=socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    if(ConnectSocket == INVALID_SOCKET)
    {
        printf("Error at socket(): %ld\n", WSAGetLastError());
        WSACleanup();

        getchar();
        return 0;
    }

    sockaddr_in clientService;

    clientService.sin_family = AF_INET;
    clientService.sin_addr.s_addr = inet_addr("127.0.0.1");
    clientService.sin_port = htons(80);

    if(connect(ConnectSocket, (SOCKADDR*)&clientService, sizeof(clientService)) == SOCKET_ERROR)
    {
        printf("Failed to connect.\n");
        WSACleanup();

        getchar();
        return 0;
    }
	else
	{
		printf("Conect to server... OK! \n");
	}

    int bytesSent;
    int bytesRecv = 0;
    char sendbuf1[] = 
				"POST /index.php?action=dologin&username=123&password=123 HTTP/1.1\n"
				"User-Agent: Opera/10.00 (Windows NT 6.0; U; en) Presto/2.2.0\n"
				"Host: test2.ru\n"
				"Proxy-Connection: Keep-Alive\n"
				"\n";
    char recvbuf[99999] = "";
	bytesSent = send(ConnectSocket, sendbuf1, strlen(sendbuf1), 0);
    printf("Bytes Sent: %ld\n", bytesSent);
    bytesRecv = recv(ConnectSocket, recvbuf, 99999, 0);
    printf( "Bytes Recv: %ld\n", bytesRecv );


    closesocket(ConnectSocket);
    WSACleanup();

    getchar();

    return 0;
}