For my reference, Halliburton (HAL), the American natural gas producing company, was Added to Goldman Sach's (research) Conviction Buy List today, 4/30/08.
Coincidentally, Goldman's Conviction Buy List also currently lists Conoco Phillips (COP) as its #1 Integrated Oil company (FYI, COP also has great exposure to natural gas - please refer to some previous 'Conoco Phillips' posts).
Full Disclosure: I own shares of HAL and COP.