[marcoszorrilla]

Código Delphi [-]
procedure TfrmNeedData.FormCreate(Sender: TObject);
var
  i: integer;
begin
  SomeList := TStringlist.Create;

  for i := 0 to 500 do
    SomeList.Add('Line ' + IntToStr(i));
end;

procedure TfrmNeedData.QuickRep1BeforePrint(Sender: TCustomQuickRep;
  var PrintReport: Boolean);
begin
  // You must reset your data in the BeforePrint event
  // or when you print from the preview, the report will
  // start with the last value(s)
  CurrentIndex := 0;
end;

procedure TfrmNeedData.QuickRep1NeedData(Sender: TObject;
  var MoreData: Boolean);
begin
  // If MoreData is true, then QuickReport will print
  // another detail band.  When you set it to false,
  // the report is done.  

  MoreData := (CurrentIndex < SomeList.Count);

  if MoreData then
  begin
    QRLabel1.Caption := SomeList[CurrentIndex];

    // Here's how to set the progress bar
    QuickRep1.QRPrinter.Progress := (Longint(CurrentIndex) * 100) div SomeList.Count;
  end
  else
    QuickRep1.QRPrinter.Progress := 100;

  Inc(CurrentIndex);
end;

Este ejemplo lo trae el propio QuickReport en la carpeta Demos de Delphi.

Un Saludo.