Nigerian Letters

The most commonly reported scheme. Typically involves a proposal to move tainted funds out of a third world country. Frequently in ALL CAPS.
Also known as a "419 Scam", Nigerian Letters have been around for years. They were traditionally sent to small business owners through the U.S. mails. As the Internet has become more widely available, Nigerian letters have become more prevalent.
Many of these solicitations originate outside of Nigeria. They are still called Nigerian Scams.
The exact wording and content of these e mails vary, but run along the same general theme. The sender introduces him or her self as a son, daughter, widow, or aide to a governmental minister, general, or wealthy individual who has died. The sender expresses a desire to find a trustworthy individual who is willing to assist in transferring vast sum of money typically $10 million or more which belonged to the deceased individual. The funds are described as "lost" that is, no one has a legitimate claim on them. The sender needs the help of a stranger in the U.S. so as to avoid having the funds confiscated by their government. The sender asks for some or all of the following items:

o A signed letter of commitment that you will keep the transaction strictly confidential.
o Your ID or driving license number.
o Your telephone and fax numbers.
o Your full permanent address.
o Your bank account information.
o A sample of your business letterhead.

There is often a breakdown of how the funds will be divided, with 5% to 10% allotted to expenses, 20% to 30% for you, and the remainder kept by the sender. There is a strong emphasis on keeping the transaction confidential. There is often a suggestion that the transaction is somewhat if not completely illegal.
If you receive a Nigerian Letter, you will be best served by deleting it without responding. Unless you have suffered an actual, financial loss by responding, there is little utility in sending a copy of the solicitation to the FBI or the U.S. Secret Service (USSS). The sender will not be concerned if you reply by telling him you are sending a copy to the FBI, USSS, or any other law enforcement agency.
The most effective way of addressing these solicitations is to ignore them and to tell anyone who receives one to ignore it. If you or someone you know has suffered a loss as a result of attempting to participate in one of these offers, they should contact their local FBI office and provide details of the loss. Alternatively, written documentation may be sent to the United States Secret Service, Financial Crimes Division, 950 H Street, NW, Washington, D.C. 20223, or telephone (202) 406 5850, or contact them by e mail (419.fcd@usss.treas.gov ) or by completing the online form found at http://www.ustreas.gov/usss/contact_fcd.shtml. The USSS maintains a webpage concerning this type of fraud which can be accessed via http://www.ustreas.gov/usss/alert419.shtml.
There are a number of websites devoted to sharing information concerning Nigerian Letter Scam. Using the terms "Nigerian", "letter", and "fraud" at your favorite search engine should identify several for you. A well documented description of this type of fraud, complete with sample letters/e mails, can be found at snopes.com.