Signed into law in March 2010, the Affordable Care Act (aka “Obamacare”) is a long and complex piece of legislation designed to reform the US healthcare system. The primary goals are to improve access to healthcare, improve care quality, and slow the increase in national healthcare costs.
You can read an excellent “plain English” overview here: http://www.hhs.gov/healthcare/facts/timeline/timeline-text.html
The law actually consists of two parts, the Patient Protection and Affordable Care Act, and the Health Care and Education Reconciliation Act. You can read the full 955 page piece of legislation here, but it’s not exactly light reading. Don’t say we didn’t warn you: http://housedocs.house.gov/energycommerce/ppacacon.pdf