Over on SEOMoz I found a great little article about page jacking. Page jacking for mere mortals is a waste of time, Google will see it as duplicate content and it will probably lower your serps.
The great thing abut this article is the link to a email exchange with a lady who thought some one had page jacked her site. In this instance and little knowledge does you know good at all. Then add on paranoia and you have a very funny, if long winded email rant.