The portion of the Affordable Care Act (a.k.a. ObmamaCare) that was most vocally challenged in and out of court and ultimately upheld by the Supreme Court is the individual mandate, which requires all Americans to have basic health insurance. Below is a synopsis of the individual mandate adapted from http://www.healthcare.gov/.
Individual Mandate: Starting January 1, 2014, every individual who does not qualify for insurance through an employer, Medicare or Medicaid will be required to purchase health insurance. If an individual chooses not to purchase insurance he/she will be required to pay a penalty, though there are several waiver options for low-income individuals to avoid the penalty. A waiver can also be requested based on religious beliefs (http://1.usa.gov/iTIhH1).
Other portions of the law that might be of interest (access a timeline of the law & what takes effect when -- http://www.healthcare.gov/law/timeline/index.html)...
Insurance Exchanges: Also effective Jan 1, 2014, the insurance exchange program allows individuals and businesses more versatility to shop for and choose an insurance plan that best meets their need and budget(http://1.usa.gov/r7bI0A).
Medicaid: The law sought to increase access to Medicaid, the court decision restricted this... from the New York Times "The decision did significantly restrict one major portion of the law: the expansion of Medicaid, the government health-insurance program for low-income and sick people. The ruling gives states some flexibility not to expand their Medicaid programs, without paying the same financial penalties that the law called for."
Tax Credits for Insurance: Tax credits to help the middle class afford insurance will become available for those with income between 100% and 400% of the poverty line who are not eligible for other affordable coverage.
More Choices for Workers: Workers meeting certain requirements who cannot afford the coverage provided by their employer may take whatever funds their employer might have contributed to their insurance and use these resources to help purchase a more affordable plan in the new Affordable Insurance Exchanges.
The debate and challenge of the Affordable Care Act is long from over. Expect more excitement and possible changes in the coming months (especially after the November election).