Law.com reports that a law suit will continue against a accused of "hacking" by accessing information in the online resource called the "Wayback Machine", at http://www.archive.org. The site indexes and stores Web site content going back many years, enabling visitors to see iterative changes to Web sites. The plaintiff had sued the Internet Archive as well, who has settled. The suit claims that law firm staff "hacked" the site to see content. Here is a post from July 2005 about the lawsuit, by William Patry @ Thelen Reid & Priest.
The Wayback Machine is less a hacking tool than an archive of crawled/indexed Web sites that one can access by typing in a URL. No skill or additional knowledge is related to finding the information once you get there. I missed this case when it first popped up last year but I'll be watching to see how it turns out!