From the IRS:

The Internal Revenue Service announced the availability of expanded Twitter feeds to share timely information with taxpayers and the tax professional community.

The IRS Twitter news feed, @IRSnews, provides the latest federal tax news and information for taxpayers. The focus of the IRS Twitter messages will be on easy-to-use information, including tax tips, tax law changes and important IRS programs such as e-file, the earned income tax credit and “Where’s My Refund.” Anyone with a Twitter account can follow @IRSnews by going to http://twitter.com/IRSnews. 

Another important IRS Twitter feed, @IRStaxpros, is designed for the tax professional community. Follow @IRStaxpros by going to http://twitter.com/IRStaxpros. The IRS also tweets tax news and information in Spanish at @IRSenEspanol. Follow this Twitter feed by going to http://twitter.com/IRSenEspanol.