use
    ..IdHTTP,ShellApi,RegExpr..;

var LoginInfo: TStrings;
    r      :TRegExpr;
    page : string;

....

    LoginInfo := TStringList.Create;
    LoginInfo.Clear;
        
    IdHTTP1.Host:='login.vk.com';
    IdHTTP1.Port:=80;
    LoginInfo.Add('op=a_login_attempt');
    try
       page := idhttp1.Post('http://vkontakte.ru/login.php',LoginInfo);
    except
       showmessage('nemogy auth');
       exit;
    end;
    if (pos('captcha_sid',page)>0) then
    begin
            showmessage('this is captchaaaaa!');
            exit;
    end;

    LoginInfo.Clear;
    LoginInfo.Add('email='+edit_login.Text);
    LoginInfo.Add('pass='+edit_pass.Text);
    page := idhttp1.Post('http://pda.vkontakte.ru/login?pda=index&acknowledge=0',LoginInfo);
    r := TRegExpr.Create;
    page := idhttp1.get('http://pda.vkontakte.ru/status');
    if (pos('name="activityhash"',page)<=0) then begin
        showmessage('bad login \ pass');
        exit;
    end;
    showmessage('good login \ pass');