The attached list of hyper links will lead you to greater knowledge on the subject of Hydraulic Fracturing but may raise more than a few questions. Much of the writing is done by people with an axe to grind so caution against jumping to conclusions is advised. I have read a lot more than what is included here and in the articles that are included on the web site and about all I can say definitively is: 1) I tend to be in favor of the process if done with caution and care. 2) There are far more questions and accusations than proof of attributed causes.
Links to fracking sites:
http://en.wikipedia.org/wiki/Hydraulic_fracturing general information
http://www.sourcewatch.org/index.php?title=Fracking general information
http://www.washingtonpost.com/blogs/ezra-klein/wp/2012/07/16/how-states-are-regulating-fracking-in-maps/ news on regulation efforts
http://www.redstate.com/vladimir/2012/07/04/natural-gas-economics-a-look-under-the-hood/ financial point of view