Chain Letters Anonymous: Service which allows people to safely send a chain letter without the risk of 'bad karma'.
Chain letters promising get rich quick schemes: Article covering the basic of chain emails, the profits that can be created by a hypothetical pyramid scheme and tips on how to avoid them.
E-mail bonding: A wealth of messages: That Johnathan Rourke guy? Can't be found by reporter. The claims in the popular "reports" MMF chain letter about its legality are false. [Seattle Times]
E-Mail Chain Letters: University of Oklahoma Police Department advisory regarding e-mail chain letters and hoaxes.
Make Money Fast: Short article on this illegal pyramid scheme, which is typically spread by e-mail and Usenet spam or bulletin board posts.
Pyramid selling & chain letters: PDF document from the Office of Fair Trading in Australia, outlines how to report a pyramid selling scheme.
The Make Money Fast Myth Page: Be warned - you are likely to be harassed by angry recipients if you send on chain emails, and your Internet account could be terminated.