http://www.msnbc.msn.com/id/8171053/But Nigerian scams stretch far wider than e-mails asking for help moving money out of international accounts. In a much more elaborate version of the crime, scammers participate in legitimate online auctions, finish with the high bid, and send along a check to pay for the winnings.
The payment often arrives as a cashier's check, thought to be good as cash by many U.S. residents. It's not.
The criminal sends more than the winning amount and asks for some to be wired back. When victims apparently successfully deposit the cashier's check, they figure the buyer is legit, and wire the overage, often to a bank account in Nigeria. Weeks later, the bank discovers the cashier's check is bogus, and the depositor is responsible for the missing funds. Often, the victim is out both the merchandise and the money.
In another variation, Nigerians offer to donate money to charities they find online; then, they follow the same tactic. A too-big check is sent and a partial refund requested.