Ultra Petroleum Corp. (AMEX:UPL) -- UPL is down from a high of over $70 per share ealier this year to its current levels of around $48. Despite this drop, the company is still currently trading above enterprise value with a PEG of 1.21, which is slightly below the industry average.

CNX Gas Corporation (NYSE:CXG) -- CXG is a new public company trading nearly even since its IPO, currently sitting around $25 per share. The company is trading above its enterprise value, but has a PEG of around 0.98 - lower than the industry average.

XTO Energy Inc. (NYSE:XTO) -- XTO has been rangebound throughout this year, currently trading around $47 per share. The company currently trading well below enterprise value with a PEG of just 0.66 - substantially lower than the industry average. This makes XTO one of the cheapest companies in the oil and gas sector.

EOG Resources, Inc. (NYSE:EOG) -- EOG is off its 2006 highs of around $80 per share, currently standing at $63 per share. The company is trading just about at enterprise value with a PEG of 1.33.

Range Resources Corp. (NYSE:RRC) -- RRC is currently trading above the major moving averages at around $27 per share. The company is trading below enterprise value with a PEG of right around 1.15, making it a relatively attractive company from a value perspective.

Occidental Petroleum Corp. (NYSE:OXY) -- OXY is currently trading above its yearly lows of around $40 per share, currently sitting at close to $60 per share. The company is trading slightly below enterprise value with a PEG of 1.09.