procedure TForm1.Button1Click(Sender: TObject);
var
data: TStringList;
begin
data := TStringList.Create;
try
{add the used parameters for the script}
data.Add('login=111');
data.Add('passwd=222');
data.Add('submit=Âîéòè');
{ Call the Post method of TIdHTTP and read the result into TMemo}
Memo1.Lines.Text := http.Post('http://mail.yandex.ru/pda/', data);
finally
data.Free;
end;
end;