This
Bookmarklet takes the current page and looks for archived versions of that page in the Internet Archive
(
http://www.archive.org).
This is especially useful for dead links or for finding older versions of a specific page.
The JavaScript code for this Bookmarklet is:
javascript:(function(){%20location.href='http://web.archive.org/web/*/'+location.href;%20})();
Here is the link for this Bookmarklet (drag and drop it into your bookmarks):
Archive.org Bookmarklet