Do a thorough background check on any “work-from-home” opportunity before giving any of your personal information – this will help protect you from identity thieves (and thieves in general) who want to steal your information or hire “work-for-free” employees.
While working from home certainly seems appealing, many of the work-at-home opportunities out there are scams, often requiring you to reveal personal information, or charging you money for work-at-home information you can find free anywhere on the internet.
Are there legitimate work-from-home opportunities? Of course there are. There are companies out there that will pay you to blog for them, or companies which allow telecommuting. But, when they promise an incredible amount of money for a few hours of work a week, you know it's time to look elsewhere. Legitimate companies are pretty up front how much they will pay you to work from home. Hint: you're not going to get rich from it.
Having said all that, if you have an expertise in something, it is possible make a decent side living, or, in some cases, a full-time living, working at home. For example, about.com pays experts to become guides on a whole range of subjects and get paid for it. If it's a popular topic, you can make a decent living. But, you really have to be an expert on something, and be able to write about it. You can check out which topics are available and the qualifications at beaguide.about.com