From http://www.irs.gov/uac/Tax-Scams-Consumer-Alerts

If the phone isn't answered, the scammers often leave an “urgent” callback request.

Note that the IRS will never: 1) call to demand immediate payment, nor will the agency call about taxes owed without first having mailed you a bill; 2) demand that you pay taxes without giving you the opportunity to question or appeal the amount they say you owe; 3) require you to use a specific payment method for your taxes, such as a prepaid debit card; 4) ask for credit or debit card numbers over the phone; or 5) threaten to bring in local police or other law-enforcement groups to have you arrested for not paying.

Automated voice recording stating that the Irs has a law suit against me !

Just got a phone call telling m this is the last notice I will receive before the IRS files a lawsuit against me. This the second one I  received in the last six months. I know this is a scam just wanted to let people know.

Just received one of these recorded messages stating I owe the IRS money. When I called back, someone did answer stating they were the IRS. I hung up rather than reply because I knew it was a scammer. Would like to know if there is a legitimate place to report this.

I answered the main phone AT WORK from this number just now, and it was just like the others described above - recorded message instructing me to call a caseworker regarding a pending lawsuit from the IRS.  Obviously, it is a scam.