[M.A.D.M.A.N.]

Код:

uses idhttp; // forget!
.....
Var FS:TMemoryStream;
    idhttp:TIdHTTP;  //forget!
begin
  idhttp:=TIdHTTP.Create(nil);  //Forget!
  FS:=TMemoryStream.Create;
  IdHTTP.Get('http://you_site/f.txt', FS);
  fs.SaveToFile('f.txt');
  FS.Free;
  idhttp.Free;//forget!
end;