Source: http://feeds.gawker.com/~r/lifehacker/full/~3/UNz5SEjVi-Y/backupurl-takes-snapshots-of-web-pages
To create a snapshot, simply go to BackupURL, paste in the link to the page, and click the Backup button to generate the cached copy, which is accessible from an already-shortened URL. The web application is very simple, and the lack of information makes it questionable for long-term archiving, but it could be very useful for saving a quick copy of a constantly changing news site for sharing with others.
For a similar service with more features (although requiring a browser extension), check out previously mentioned Iterasi, or you can save a web page as an image with PageSaver.