I got a call from this number as well. They always do this during tax season. Apparently I owe the IRS money. The funny thing is I have not only finished my tax returns but I have gotten my refund from them as well. If I mention that to them, they say that there was an error. Its extremely irritating. I would rather get arrested than listen to this message :)
To those who might think this is the IRS, please remember that you can always go on the IRS website and get in touch with them directly. Also, they always write to you (e-mail or mail) and never calls.