A huge amount of information on green building and green building products, compiled and commented on by people who know this field. Their free-access GreenSpec directory contains entries to "more that 1,800 environmentally-preferable building products with descriptions, manufacturer information and links to additional resources." All listings are screened and written by their experienced staff. Also take a look at their article "What Makes A Product Green?" . They also publish a the well-regarded Environmental Building News and have much more information on their site. This site is pretty nuts-and-bolts, geared more to professional architects and builders, and gives more information that you may need or want to know as a homeowner, but it is a great resource for anyone interested in green building.