Code:

procedure TForm1.Edit1Change(Sender: TObject);

begin

CurPos := Edit1.SelStart;

Label1.Caption := IntToStr(CurPos);

end;

procedure TForm1.Edit1KeyDown(Sender: TObject; var Key: Word;

Shift: TShiftState);

begin

If Key = VK_LEFT then dec(CurPos);

if Key = VK_RIGHT then inc(CurPos);  

Label1.Caption:= IntToStr(CurPos);

end;