Overview:

As a fuel, natural gas is convenient and efficient. It is used primarily for heat, in industrial, commercial and residential settings. In many homes the house and water are heated by gas, the food is cooked with it and clothes dried. Gas is also used to produce electricity, in some cases using gas fired turbines that are similar to jet engines, in others to fire steam boilers. Small gas-fired generators, called micro turbines, have recently been introduced. Gas is often used to heat industrial and commercial boilers and pressure vessels.

Trade Associations:

American Gas Association
American Boiler Manufacturers Association.
Gas Appliance Manufacturers' Association.
International Association for Natural Gas Vehicles.
National Association of Manufacturers
Society of Automotive Engineers

Yahoo Sites:

Business and Economy: Companies: Energy: Petroleum: Natural Gas.
Science: Energy: Petroleum: Natural Gas.

Regulation: Use of natural gas per se is not regulated, except for workplace safety regulations.

Energy Information Administration (home page)
Energy Information Administration Natural Gas Page

Trade periodicals:

American Gas Magazine covers gas use issues.

Other sources:

American Society of Mechanical Engineers sets standards for boilers and pressure vessels.
The Gas Research Institute does research on gas supply and use issues.
The Institute of Gas Technology looks at technology aspects of gas production and use.
Natural Gas Information and Educational Resources is an industry-wide collaborative effort to educate the general public on natural gas without company-specific overtones.
NaturalGas.com

Sample firms:

ABB Combustion Engineering is a global construction firm based in Switzerland.
ABCO Industries is a Texas boiler maker.
Advanced Alternatives Energy Corp. is a global constructor from Kansas.
Bechtel Fossil Power Co, based in MD, is a subsidiary of San Francisco's Bechtel, one of the world's largest engineering & construction firms.
CH2M Hill is a global engineering firm
DB Riley Inc. is a boiler manufacturer.
Deltak, a unit of Jason Industries, is a global boiler builder.
Ely Energy Inc.'s Synthetic Natural Gas is a substitute for natural gas during natural disasters or other service interruptions.
GPU International, a subsidiary of a large US utility, is a natural gas marketer.
Harza Engineering, based in Chicago, has offices worldwide.
Kewanee Boiler Manufacturing Co, in Kawanee IL, supplies gas-fired boilers globally.
Korea Heavy Industries and Construction Co is a major constructor of gas-fired facilities.
M.W.Kellog Co is a global engineering firm.
Mitsui Babcock Energy builds boilers and has offices worldwide.
North American Energy Services operates gas fired combustion turbines, boilers and commercial heating systems.
Perry Machinery is a major boiler maker based in NJ.
R. W. Beck finances gas-fired power and industrial systems globally.
Siemens builds, installs and operates gas turbines.
Stone & Webster provides energy and industrial engineering and construction services.