Some details according to Kerry Eleveld over at the Advocate:

Congress passed the policy reversal last summer under the leadership of Sens. John Kerry (D-MA) and Gordon Smith (D-OR) and Congresswoman Barbara Lee (D-CA); former President George W. Bush signed it into law, but the Administration was unable to finalize the change before his term ended.

The new regulation eliminates any travel and immigration restrictions that are tied to a person's HIV status. The Department of Health and Human Services (HHS) put the wheels of change in motion in late June by publishing the proposed regulation to the federal register, which triggered a 45-day public comment period. HHS has now sent the final change to the Office of Management and Budget for approval, but the source said HHS would not be able to fully implement the new regulation for another 60 days following the president's announcement.

In the intervening months, the U.S. Citizenship and Immigration Services has directed its officers to place holds on any decisions regarding green card applications that are based solely on an individual's HIV status pending full implementation of the new rule.

Immigration Equality, which has been pushing for lifting the restrictions, had this to say:

We are proud to have been part of a tremendous coalition, including Senator John Kerry, former Senator Gordon Smith, and Congresswoman Barbara Lee, who have worked tirelessly to repeal this ban.  Every day, Immigration Equality hears from individuals and families who have been separated because of the ban, with no benefit to the public health.  Now, those families can be reunited, and the United States can put its mouth where its money is: ending the stigma that perpetuates HIV transmission, supporting science, and welcoming those who seek to build a life in this country.  Today's announcement is proof that immigration laws that separate families and stigmatize communities are always destined to fail.

Also key was the extension of the Ryan White Act. The three-year extension of the lifesaving legislation funds an array of innovative and effective services that form the healthcare safety net for uninsured and underinsured Americans living with HIV/AIDS. According to the Government Accountability Office, the program helps about 500,000 annually.

The Ryan White Care Act, first enacted in 1990, is the nation's largest federally funded program for people living HIV/AIDS.