From the IRS web-page: http://www.irs.gov/newsroom/article/0,,id=233926,00.html

The IRS uses social media tools and platforms to share the latest information on tax changes, initiatives, products and services. These social media platforms include YouTube and Twitter. A listing is available on IRS.gov.
YouTube
The IRS has short and informative YouTube videos on tax related topics in English, American Sign Language (ASL) and a variety of foreign languages:
IRS Videos – http://www.youtube.com/irsvideos
ASL Videos – http://www.youtube.com/IRSvideosASL
Multilingual Videos – http://www.youtube.com/IRSvideosMultilingua
Twitter
IRS tweets include various tax-related announcements, news for tax professionals and hiring initiatives:
@IRSnews – http://twitter.com/irsnews
IRS news and helpful information for the public, the press and practitioners
@IRStaxpros – http://twitter.com/irstaxpros
IRS news and guidance for tax professionals
@IRSenEspanol – http://twitter.com/irsenespanol
Información, Comunicados de Prensa y Noticias en Español del IRS
News and information in Spanish from IRS
@RecruitmentIRS – http://twitter.com/recruitmentirs
IRS Human Capital Office
@YourVoiceatIRS – http://twitter.com/yourvoiceatirs
Taxpayer Advocate Service
Audio Files for Podcasts
The IRS creates audio files for use as podcasts. Each short audio recording provides information on one tax related topic. The audio files and their transcripts can be found in the Multimedia Center on IRS.gov. These files are also available as podcasts on iTunes.