There are several types of employment scams. The most notorious tricks include being recruited for an illegal job; identity theft through job applications, and bogus employment fees.
Fraudulent job opportunities often involve work-at-home offers. One of the newest appearing on job boards is the "reshipper." You are offered a good salary for receiving packages at your house and reshipping them overseas. The scam has several complicated layers, but basically, you pay out-of-pocket to ship the packages overseas, you get paid with a fake check, and the packages were paid for with stolen and fake credit cards.
An added hit to this scam: The information you provided in your job application made you a victim of identity theft. The scammers then use your information to apply for credit cards to buy more merchandise.
Other scammers don't bother to create the elaborate reshipping scheme -- they just tell you that you got whatever fake job they posted, then request your personal information "for the human resources department" and use it to steal your identity.
While hunting for a job, you may encounter someone who promises you a job, but only if you will pay a fee for processing, administration or uniforms. Steer clear of these people even if they promise you a money-back guarantee. Use employment services that charge the employer -- not the potential employee. Don't pay fees for uniforms. If you must pay for a uniform, ask that it be taken out of your first paycheck.