404ErrorPages.com is a comprehensive guide to everything that a webmaster needs to know about 404 error pages.  It covers topics such as HTTP status codes, tracking and preventing 404 error pages, and the qualities of a good 404 error page.  The website also provides a tutorial for creating a customized 404 error page.  You can find many examples of well done 404 error pages, including creative ones.  404ErrorPages.com is brought to you by the creators of Aviva Directory.