On June 26th, 2012, the Supreme Court voted to largely uphold the Patient Protection and Affordable Care Act (ACA), including the individual mandate, by a 5-4 ruling. The full decision is available here, and an analysis of possible implications on the healthcare system can be found here.
The main exception was the provision for states to opt out of Medicaid expansion. Florida and South Carolina have announced that they will opt out of the Medicaid expansion, and officials from other states such as Missouri, Mississippi, Nebraska, Mississippi and Texas have indicated that they will likely opt out also.