The natural gas market is getting a lot of attention from Jim Cramer, host of CNBC’s Mad Money program. In fact, the influential stock market analyst has called 2008, “the year of natural gas.”

In the past few months, he has recommended Anadarko, Apache, Chesapeake Energy, Devon Energy, XTO Energy, El Paso Corp. and Southwestern Energy as strong stocks.

Why is Cramer backing the natural gas industry? He says it is the “fuel of the future” because it is cleaner than the other alternatives. He also cites the fact that natural gas prices are still much lower than oil prices, which is bound to change given their traditional pricing averages.

In addition, Cramer has backed big oil companies with exposure to natural gas since they have seen 33% gains in their stock since oil prices jumped from $100/bbl, to $130/bbl. In that time frame, companies such as ExxonMobil and Marathon Oil have not experienced significant stock increases.

The company he has backed the strongest is Anadarko because of its improved balance sheet and its increasing exploration activity. Cramer also cited the company’s 15 year growth record, ability to create value for its shareholders and its Western Gas IPO as positives.

Since he recommended Anadarko on his blog in May, the company’s stock has gone from trading at about $68 per share, to a high of $79.86 per share last month. The stock has since come back down to about $68 per share.

Cramer picked Apache because of the three shale gas wells the company discovered in British Columbia, which may hold between 9 and 16 trillion cubic feet of gas. He calls the company “the single best natural gas stock play in the world.”

Since he backed Apache, the stock has gone from under $100 per share to its current level of about $122 per share with a high of about $146 per share in May.

Chesapeake Energy was backed because of the large amount of insider buying in the company, including heavy stock accumulation by its CEO, which shows faith in the company. He also cited its strong production growth, which is expected to hit 21% this year.

Cramer wrote up a recommendation for Chesapeake Energy in March when the stock was at about $44 per share. It is currently trading at about $60 per share and hit its high since his buy recommendation of $69 per share last week.

Cramer has stated that Devon Energy will beat its Q2 estimates handily and perfectly fits his description of a big oil company involved in natural gas production.

The company has a hit a high of about $123 per share multiple times in the period since the company was mentioned as a buy on the program in November. At the time the stock was trading at $85 per share. It is currently priced at about $108 per share.

XTO Energy was an early natural gas stock favored on Mad Money. In fact he has called XTO the best of the natural gas companies. He has backed the company since February. In that time, the company’s stock has gone from $55 per share, to $60 per share, with a high of $73 per share in June.

El Paso was described as a cheap way for viewers to play in the natural gas stock market by Cramer. He cited the company’s slower growth rate in the stock market in comparison to the rise of similar companies as a major investment incentive. He stated that this slower growth was likely due to the company’s combination of drilling, production and pipeline segments confusing the market.

This recommendation has done little to change the stock’s movement, as it has gone from $18 per share when he first spoke of it in April to about $19 per share currently. It has reached a high of about $21 per share multiple times during that period.

Southwestern Energy is Cramer’s most recent natural gas pick. The company was described as the cheapest natural gas play in the stock market because investors were focusing on the Haynesville, Fayetteville and Marcellus shales instead of the Barnett Shale.

Cramer stated that the company’s focus on the Barnett, as well as their recent induction into the S&P 500, which will provide them with added institutional ownership are major positives.

The stock jumped 6% on the day he recommended it. Since then it has fallen about $7 per share, from $48 per share, to $41 per share, which it is currently trading at.

His most recent recommendation in the natural gas field is Spectra Energy, which he recommended last week due to its lack of volatility and the $3 billion worth of projects in the pipeline. Thus far, the stock’s price has remained flat at $27 per share.