USCIS has issued a memo implementing the US Supreme Court’s decision in overturning DOMA (the Defense of Marriage Act). In a statement, SecretaryNapolitano stated:
After last week’s decision by the Supreme Court holding that Section 3 of the Defense of Marriage Act (DOMA) is unconstitutional, President Obama directed federal departments to ensure the decision and its implication for federal benefits for same-sex legally married couples are implemented swiftly and smoothly. To that end, effective immediately, I have directed U.S. Citizenship and Immigration Services (USCIS) to review immigration visa petitions filed on behalf of a same-sex spouse in the same manner as those filed on behalf of an opposite-sex spouse
In determining your ability to file, USCIS will generally look at the legality of the marriage in the State or Country in which you were married, not at the legality in the State in which you live. Below is a link to the USCIS webpage which has some additional information. It should also be noted that Secretary Kerry also issued a statement that the DOS will be revising its policies to come in compliance as well.