Tips on Evaluating Information using the web (edited 11/06/04 Copyright The Garlic Press 2004)
Two things we want to examine are the (a) claims and the (b) credibility of the source (both the organization and the specific author)  
(a) One of the best techniques is to closely read the information.  Social scientist call it "face validity", critical thinking texts call it "background knowledge and experience" in conversation we call it "common sense" but the point is does the information appear to us to be true, accurate, etc.
(b) Questions to ask about the source organization include purpose, bias, authority and questions about the author's credibility include education, experience, reputation, accomplishments, positions. 

Beyond this the following web tips should give some help:
(1) The domain is a good start.  The .com (commercial), .org (orginization intended for non profits), .net (internet service provider) all seem to be clear in the types of organizations.  What is not realized however is anyone can apply for and receive a domain name for these as well as a number of other domains no proof of real connection to the purpose of the domain is necessary. This is not true for .edu (education) or .gov  but who knows about sites for other countries with these domains

(2) Back up the URL to determine  the server for this web site.  For example doing so with this web page finds that the site is CSUB at: http://www.csub.edu

(3) http://www.sree.net/tips/hoax.html Below you will find a set of links that deal with hoaxes and other pages with credibility problems. Be careful out there!

(4) http://www.anovember.com/articles/zack.html Some good tips and an example of the effort of a 14 year old high school student uncovering the credibility of a web site.

(5)  To find information about the owner of a web site "Google" the owner, organization, etc. and check the links that turn up.  Just for fun try to Google yourself.  You can also use Google to check out non web sources (text authors, organizations, etc.)

Additional Questions and Resources on evaluating credibility of web sources (from PC World 4/2004)
(6) Look for an "About Us" (if there is none be weary of information), a physical address or a phone number

(7) No privacy policy on pages that want information from you should make you question the purpose and the information provided

(8) Approach a web site like you would a magazine, book, newspaper on a rack and ask "Who are these people, what do they say about themselves, what do they expect/want from me. From Sherman, Chris and Price, Gary The Invisible Web

(9) To possibly find information about the owner of a web site and may be an address, phone number etc. try:

http://www.geektools.com/whois.php
Or
http://www.allwhois.com/cgi-bin/allwhois.cgi

(10) To find how often a site has been accessed and how long online (works OK with major sites not to good with sites of small groups according to PC World:

http://www.alexa.com/

(11) For a list of links to groups that seek to educate the public about bad information on the internet try:

http://www.virtualchase.com/quality/alert.html