unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, IdBaseComponent, IdComponent, IdTCPConnection, IdTCPClient,
  IdMessageClient, IdPOP3, StdCtrls, IdMessage, ComCtrls;

type
  TForm1 = class(TForm)
    ....
    IdMessage1: TIdMessage;
    ListView1: TListView;
    procedure Button1Click(Sender: TObject);
  private
    { Private-Deklarationen }
  public
    { Public-Deklarationen }
  end;

var
  Form1: TForm1;
  intindex: integer;
  itm : tlistitem;
implementation

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
begin
 pop.Host := 'pop.gmx.net';
 pop.Username := '11260803';
 pop.Password := '922244';
 pop.connect;

 label1.caption := inttostr(pop.CheckMessages);
 label2.caption := inttostr(pop.RetrieveMailBoxSize div 1024);
 pop.RetrieveHeader(intindex,idmessage1);

end;

end.