[marcoszorrilla]

procedure TForm1.Button6Click(Sender: TObject);
begin
  NMSMTP1.PostMessage.FromAddress := Edit6.Text;
  NMSMTP1.PostMessage.FromName := Edit5.Text;
  NMSMTP1.PostMessage.Subject := Edit10.Text;
  NMSMTP1.PostMessage.ToAddress.Add(Edit7.Text);
  NMSMTP1.PostMessage.ToBlindCarbonCopy.Add(Edit9.Text);
  NMSMTP1.PostMessage.ToCarbonCopy.Add(Edit8.Text);
  NMSMTP1.PostMessage.Attachments.AddStrings(Listbox1.Items);
  NMSMTP1.PostMessage.Body.Assign(Memo1.Lines);
  NMSMTP1.SendMail;
end;

Este ejemplo completo lo tienes en la carpeta de Delphi Demos\Fastnet\Smtp.

Un Saludo.