Via Bag and Baggage  and Inter Alia comes this story that in a pretrial evidentiary ruling, a magistrate judge in the Northern
District of Illinois held that “snapshots” taken by the Internet
Archive that depict web pages as they appeared in the past are admissible under the Federal Rules of Evidence.

In a trademark breach case, the defendant sought to use the plaintiff’s own web site as evidence of the real intention of the plaintiff.To overcome the plaintiff’s claim of hearsay the party offering the pages from the Archive also included an affidavit from an Internet Archive employee, to authenticate the documents.

I’m not aware of Australian cases under those circumstances but it is certainly good practice by a plaintiff in domain name, copyright and trademark dispute cases to print out the web pages in dispute and the code as soon as the breach is identified and to make sure the printout has the url and date.

UPDATE: I should mention that there are sites which will monitor websites for changes including WebSite-Watcher , Infominder and TrackEngine.

I use Watch That Page (free).