[Kapitoshka438]

Код:

procedure TForm1.DBGrid1CellClick(Column: TColumn);
begin
  if Column.FieldName = 'Date' then
  begin
    DateTimePicker1.DateTime := Table1.FieldByName('Date').AsDateTime;
    DateTimePicker1.Left := Mouse.CursorPos.X - Left - 5;
    DateTimePicker1.Top := Mouse.CursorPos.Y - Top - 30;
    DateTimePicker1.Show;
  end;
end;

procedure TForm1.DateTimePicker1Change(Sender: TObject);
begin
  Table1.Edit;
  Table1.FieldValues['Date'] := DateTimePicker1.DateTime;
  Table1.Post;
  DateTimePicker1.Hide;
end;

Примерно вот-так, сами подгоните код, как вам удобно.