If you get a phone call from the IRS saying that you owe past taxes and if you do not pay you will be arrested, hang up the phone. This is a phone scam, and unfortunately not the only one.
Other phone scams ask victims to donate to a charity by wiring money, or say that you've won a prize but you can't get it until you send money, or that your relative is being held captive until you send money. To prevent being a victim of a phone scam, do not send any money to people you don't know personally. And don't give out personal or financial information to unknown callers.