more materials about environment impact u mean? just few things from my bookmarks ale uz neviem ako su actualne,,,

loss of habitat
impact on birds [higher mortality - but it depends on location, esp.coastal..]
impact on bats [due to sounds, heat and electromagnetic fields that lure them]
http://www.sfgate.com/cgi-bin/article.cgi?file=/c/a/2007/05/04/MNG9SPKPT31.DTL
http://www.ncpa.org/studies/renew/renew2d.html

and one quotation from a blog:
"The damn things are noisy. And it doesn't stop. Burrowing rodents living among the windmills are suffering from stress; which impacts health and fertility. I wonder what the long term impact might be."

didnt double check those articles, so might be outdated or simplistic...