In the course of a busy day, you may write a check at the grocery store, charge tickets to a ball game, rent a car, mail your tax return, change service providers for your cell phone, apply for a credit card, or do any of a number of things that involve revealing your personal information. And chances are you don't give these everyday transactions a second thought. But an identity thief could use any one of them to steal your identity and in a matter of minutes and seriously damage your credit rating.