From Obama's presidential campaign website:
"NEW AFFORDABLE, ACCESSIBLE HEALTH INSURANCE OPTIONS. The Obama-Biden plan will create a National Health Insurance Exchange to help individuals purchase new affordable health care options if they are uninsured or want new health insurance. Through the Exchange, any American will have the opportunity to enroll in the
new public plan or an approved private plan, and income-based sliding scale tax credits will be provided for people and families who need it. Insurers would have to issue every applicant a policy and charge fair and stable premiums that will not depend upon health status. The Exchange will require that all the plans offered are at least as generous as the new public plan and meet the same standards for quality and efficiency."
"The Obama-Biden plan provides new affordable health insurance options by...requiring all large employers to contribute towards health coverage for their employees or towards the cost of the
public plan."
http://www.dailykos.com/storyonly/2009/8/15/767136/-As-a-candidate,-Obama-supported-public-option