GreenYour.com has a categorized facts, tips and products to help you go green. Fantastic little icons that pay attention to the details of design. I enjoy how there are footnotes to some of their tips, making it easier for users to check where information is coming from, and follow up further if so inclined.
IdealBite.com has tips that are "convenient, fun and inexpensive." I don't have the experience with idealbite I would like to for a proper review. It was recommended by a friend though, and has several features I enjoy. One is city specific green tips for San Francisco, Los Angeles, New York and Chicago. Their tip library has been easily searchable. And, if so inclined, users can have tips delivered to their inbox on a daily basis.
Treehugger.com has a series of how to green various aspects of your life. Convenient are the links to other resources and places to purchase some of the items talked about. In fact, the follow up resource lists are quite extensive, and get updated by the daily posts on Treehugger if relevant.