I received a message from this phone number and was very happy that I looked it up online and found this site to let me know this was a scam!  It really should be reported!  Don't know how to go about it, but I'm sure it's someone trying to get money in a very illegal, dishonest way!!!  I pay my taxes every year and still need to do this year's taxes which put up the red flag when getting this message... the IRS office isn't even open during the weekend!

Official IRS Government site detailing this scam and providing links to report it:
http://www.irs.gov/Individuals/How-Do-You-Rep ... aud-Activity%3F

this is scam for IRS

IRS scam

You can also report the scammers directly to the IRS at www.tigta.gov.  The form is "IRS IMPERSONATION SCAM REPORTING".  Should also be reported to FTC as well but its complaint form needs to be simplified.