[angvelem]

Если ничего не напутал, то примерно так.

Код:

var
  App, Book, Sheet : Variant;
  FileName : String;
begin
  App := CreateOleObject('Excel.Application');
  try
    Book := ExApp.WorkBooks.Open(True);
    Sheet := ExBook.WorkSheets[1];
  finally
   App := Unassigned;
   Book := Unassigned;
   Sheet := Unassigned;
  end;
end;