[Страдалецъ]

Вот такой еще вариант:

Код:

procedure TForm1.DBGrid1MouseMove(Sender: TObject; Shift: TShiftState; X, Y: Integer);
Var
  CellXY: TGridCoord;
  RecNo: Integer;
begin
 CellXY := DBGrid1.MouseCoord(X, Y);
 DBGrid1.DataSource.DataSet.DisableControls;
 RecNo := DBGrid1.DataSource.DataSet.RecNo;
 DBGrid1.DataSource.DataSet.MoveBy(CellXY.Y - DBGrid1.DataSource.DataSet.RecNo);
 if CellXY.X > 0
 then begin
      DBGrid1.Hint := DBGrid1.Columns[CellXY.X - 1].Field.DisplayText;
      Application.ActivateHint(DBGrid1.ClientToScreen(Point(X,Y)));
      end;
 DBGrid1.DataSource.DataSet.RecNo := RecNo;
 DBGrid1.DataSource.DataSet.EnableControls;
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
 DBGrid1.DoubleBuffered := True;
end;