web.archive.org, most know for his "Wayback Machine"
This service allows users to see archived versions of web pages across time.
According to Internet Archive, The Wayback Machine browse through over 150 billion web pages archived from 1996 to a few months ago.
To start surfing the "Wayback" type in the web address of a site or page where you would like to start, and press enter.
Then select from the archived dates available.
The resulting pages point to other archived pages at as close a date as possible.