CheckBox - colocando dentro de uma grid

Coloque uma StringGrid e um Checkbox no form:

procedure TForm1.GridDrawCell(Sender: TObject; ACol, ARow: Integer; Rect: TRect; State: TGridDrawState);

begin

  if (ARow = Grid.Row) and (ACol = Grid.Col) then

    CheckBox1.SetBounds(Grid.Left + Rect.Left + 1, Grid.Top + Rect.Top + 1, Rect.Right - Rect.Left, Rect.Bottom - Rect.Top);

end;