If you're considering the magnets that are widely available today, read about this ripoff.
Here are some other sites reporting on quackery:
Quackwatch - the definitive starting point for this sort of thing.
The National Council for Reliable Health Information is another good portal.
National Council Against Health Fraud
Medical Quackery Alive and Well is a good introductory article on the subject, from the Mayo Clinic's Health Oasis. The Mayo Clinic used to have a list of places to report quaackery, which is here.
Interested parties can subscribe to several newsletters pertaining to quackery here and at this archived page.
To learn how to evaluate health websites, people should visit the Health on the Net Foundation. This is an international body based in Switzerland that promotes the HON Code of Conduct for online health information. Sites that meet their standards may display the HON logo (something folks should look for).
Also, see The Skeptic's Dictionary of Alternative Medicine
And for fun, the Museum of Questionable Medical Devices! OUCH!!!