Have you ever been disappointed to discover that a once-useful website address now leads to a "URL not found" error message? If so, you'll be glad to know about a tool that can help. The Internet Archive Wayback Machine is a free service that enables Internet users to access archived versions of websites dating back to 1996. Simply type in a URL, select a date, and then begin surfing on an archived version.

http://www.archive.org/