The Internal Revenue Service (IRS), in conjunction with the Department of Labor (DOL) and the Department of Health and Human Services (HHS), recently released a notice (really more of an FAQ) on issues relating to the full implement of the Patient Protection and Affordable Care Act (PPACA) in 2014.
The notice covers automatic enrollment in health insurance at work, waiting periods (not to exceed 90 days for new employees), and employer shared responsibility for securing employee health insurance at large companies.
Read NOTICE 2012-17.