I came across this article in "Rigzone" the oil-rig industry online newsletter.

http://www.rigzone.com/news/article.asp?a_id=61389

With lower inventories of Natural Gas, plus the possiblity of Hurricanes this fall and other factors promise to drive up the price of CNG. Therefore it might not be a bad idea to be prepared for CNG to go the way of Gasoline.

So read and lets hope things don't get bad.