If you are looking for what a Web site used to look like, the Wayback Machine from the Internet Archive is an excellent starting point. They have released a beta of a new version of this useful tool. The most notable feature is that they get rid of the large calendar you view after your search. Instead, it defaults to a view of the site you’re searching for, and you can then select from a small timeline at the top of the screen for a different date.
The Beta Version