For more info about pesticides:

www.epa.gov/pesticides
www.beyondpesticides.org
http://ca.water.usgs.gov/pnsp/allsum/#gw

Or info about healthy yards:

www.audubonathome.org
www.epa.gov/greenacres
www.beyondpesticides.org/pesticidefreelawns
www.botanicalmissionaries.com
http://www.nanps.org/associations/frame.shtml

Suggested reading:

articles:

Lindsey, Rebecca. "Looking for Lawns" NASA's Earth Observatory. November, 2005

Lowengart, RA, et. al. "Childhood leukemia and parents' occupational and home exposures." J Natl Cancer Inst. 1987, Jul;79(1):39-46

Robbins, Paul; Sharp, Julie."The Lawn-Chemical Economy and Its Discontents" Antipode. 2003

books:

Borman, Herbet, F., Balmori, Diana, et. al. “Redesigning the American Lawn, A Search for Environmental Harmony” Yale University Press, New Haven and London , 2001

Colborn, Theo., Dumanski, Dianne, et. al. “Our Stolen Future, Are We Threatening Our Fertility, Intelligence, And Survival?” A Plume Book, New York , N.Y. , 1997

Jackson, Kenneth., T. “Crabgrass Frontier, The Suburbanization of the United States ” Oxford University Press, New York , 1985

Jenkins , Virginia Scott. “The Lawn, A History of an American Obsession” Smithsonian Institution Press, Washington and London , 1994

Teyssot, Georges, “ The American Lawn” Princeton Architectural Press, New York , N.Y. , 1999

Wargo, John, “Our Children's Toxic Legacy, How Science and Law Fail to Protect Us from Pesticides” Yale University Press, New Haven and London , 1998

Wasowski, Andy and Sally. “The Landscaping Revolution, Garden With Mother Nature Not Against Her” The Contemporary Gardener, Chicago, 2000