Fracking is the commonly used term to describe hydraulic fracturing.
Nina Katkins, an Alliance of Nurses for Healthy Environments (ANHE) member, developed this excellent poster presentation on Marcellus Shale and fracking. Download: Marcellus Shale
The Endocrine Disruptor Exchange has an excellent resource that goes into detail about how the drills are constructed, the process, and environmental and health concerns. Read Chemicals in Natural Gas Operations. Watch this on fracking video narrated by Theo Colburn.
For more information and ways to get involved see Energy and Health.