Time-traveling is made possible using Memento, a modification of the HTTP protocol that adds a time dimension to the Web. Memento allows the browser to discover archived versions of a web page at archive.org, webcitation.org, and other repositories.
This application was created thanks to support from the Library of Congress and the National Science Foundation (Grant No. 1008492 - WAC).
For more information, visit http://code.google.com/p/memento-browser/