One of the most powerful tools the Internet offers us is its search engines, which help you search for topics throughout the whole Web. A really mind-boggling search engine is Google at http://www.google.com. Below you see the "search box" provided you when you visit Google. You can test it now by typing in something like "black widow spider" and seeing what you get. Place quotation marks around the words so the search engine will recognize the separate words as being a name, else you may get lots of pages all about the color black, the problems of widows, and spiders in general.
Google is more powerful than you can imagine. For example, the other day I wanted to know when to expect the Least Flycatcher to be migrating through my area so I went to Google and typed in "Least Flycatcher spring migration" and up came a link with the dates appropriate for a place just a state away, which was close enough. In other words, don't hesitate to search for very obscure pieces of information. If you type in a general word like "birds" you will receive information on too many pages to deal with.
There are also specialty search engines especially good for nature study, such as the Biodiversity-Ecology Search Engine at http://vlib.org/Science and the Kids.Net.Au Search Engines, especially for kids and based in Australia, at http://www.kids.net.au/ For other specialty engines look at http://www.allsearchengines.com/
Certain websites are like encyclopedias where you can browse general information about specific topics of interest to backyard naturalists. For example, Answers.com has a special Ecology Page and Botany Page, among others. Similarly, About.com presents an Endangered Species Page and an Evolution Page, among many others.
On the Internet you can download some of the great classics of nature writing at the Project Gutenberg site -- where great books so old that the copyright has passed into the Public Domain are placed so that anyone with Internet access can download them and read them for free. This is a wonderful site and if you'd like to go there right now just click on the following banner:
Here's just an example of the titles available at Project Gutenberg: