function loginvk(login, pass:string; HTTPClient:TIdHTTP):boolean;
var data:TIdMultiPartFormDataStream; s:string; res:TStringList;
begin;
HTTPClient.HandleRedirects:=True;
Data:=TIdMultiPartFormDataStream.Create;
Data.AddFormField('op', 'a_login_attempt');
HTTPClient.Post('http://vkontakte.ru/login.php', data);
data.Free;
res:=TStringList.Create;
Data:=TIdMultiPartFormDataStream.Create;
Data.AddFormField('email', login);
Data.AddFormField('pass', pass);
Data.AddFormField('expire', '');
Data.AddFormField('vk', '');
res.text:=HTTPClient.Post('http://login.vk.com/?act=login', data);
data.Free;
s:=copy(res[10], 51, length(res[10])-54);
res.Free;
if s<>'ext/css' then begin
Data:=TIdMultiPartFormDataStream.Create;
Data.AddFormField('op', 'slogin');
Data.AddFormField('redirect', '1');
Data.AddFormField('expire', '0');
Data.AddFormField('to', '');
Data.AddFormField('s', s);
HTTPClient.Post('http://vkontakte.ru/login.php', data);
data.Free;
result:=true;
end
else result:=false;
end;

s:=copy(res[10], 51, length(res[10])-54);

uses IdMultipartFormData

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');