About a year ago, I reminded you to beware of phishing.

You know, those e-mails that promise big bucks if you provide a little personal information so you can help a Nigerian diplomat's widow transfer money to the United States.

I hope none of you have fallen victim to that scam or its many variations. But I also hope you're keeping on your toes, because the scammers aren't resting on their Nigerian letter laurels. They're always trying to develop new ways to take your hard-earned money, especially during these tough economic times when they know people are more desperate than usual.

A reader named Michael wrote in about a situation his brother faced when selling some furniture on Craigslist. A person responded that she wanted to buy the furniture but couldn't call him about it because she was deaf.

"She told him her secretary would send a certified check and give him an address to drop off the furniture," Michael wrote. "Instead of the $240 price, the check arrived for $2,400. Of course the woman e-mailed my brother about the 'mistake' and asked him to wire the difference to her once he cashed it — minus $100 for his trouble.

"The check is, of course, bogus. The police said they can do nothing about this sort of thing. … I've heard of online scams, but this seemed new or different to me."

It is a fraud, Michael — a variation of the "check overpayment scam." In fact, the Federal Trade Commission has issued a consumer alert about it. People who follow through on instructions like those received by your brother soon discover that the check is a clever counterfeit, good enough to fool the average bank teller. But, unfortunately, that doesn't become clear until after the victim has wired money to the scammers.

Regarding the check overpayment scam, the FTC offers the following advice on its Web site for people who sell items online or through classifieds:

 Know whom you're dealing with. Confirm the buyer's name, street address and phone number.

 Don't accept a check for more than your selling price, no matter what. If the buyer won't send the correct amount, return the check and don't send the merchandise.

 Consider an alternative payment method. As a seller, you may suggest an escrow service or online payment service. But if the buyer insists on a particular service, and you've never heard of it, check it out before you agree. To learn more about such services, visit www.onguardonline.gov/topics/online-shopping.aspx.