how to display progress bar while mail is being sent D7/indy10

I would like to display a progress bar while mail is being sent, to indicate
to the user that something is happenning after they've pressed the 'send
mail' button. Is the a way to do this? Here's my onclick event handler code:
procedure TForm4.btSendClick(Sender: TObject);
var
td:tdatetime;
begin
td:=now;
if(length(ledto.Text) <1)or (length(ledfrom.Text) <1) or
(length(ledsubject.Text) <1) then begin
playsound('stop.wav',0,SND_ASYNC);
showmessage('Please fill in ALL the fields.');
exit;
end
else
StatusMemo.Clear;

  //setup SMTP
  sen.Host :=host1 ;
  sen.Port := 25;
  sen.Password:=pw1;

  //setup mail message
Mess2.From.Address:=ledFrom.Text;
Mess2.Recipients.EMailAddresses:=ledTo.Text;
Mess2.CCList.EMailAddresses:=ledCC.Text;

  Mess2.Subject :=ledSubject.Text;
  Mess2.Body.Text := Body.Lines.Text;


   if FileExists(ledAttachment.Text) then
    TIdAttachmentfile.Create(Mess2.MessageParts, ledAttachment.Text);

  //send mail
  try
    try
      sen.Connect;
      sen.Send(mess2);

      showmessage('Message successfully Sent at ' + datetimetostr(td) + ' to
' + ledto.Text +'!');
    except on E:Exception do
     showmessage(E.Message);
    end;
  finally
    if Sen.Connected then
      Sen.Disconnect;
  end;
end;
Thanks