Suspected Pyramid Schemes - Oregon Department of Justice site with information, hotline, and complaint form. - http://www.doj.state.or.us/finfraud/pyramids.shtml
Business Opportunities: Consumer Information - Federal Trade Commission site with tips on how to avoid scams. Most files are in PDF. - http://www.ftc.gov/bcp/conline/edcams/bizopps/coninfo.html
Shaking the Money Tree - Online article by Ami Shen Lee exposes the pitfalls of multilevel marketing. - http://www.metroactive.com/papers/metro/10.03.96/cover/multilevel-9640.html
What's Wrong with Multi-Level Marketing? - Provides an in-depth analysis of MLM and areas to be avoided. Includes links to anti-MLM research and information. - http://www.vandruff.com/mlm.html