By the United States Court of Appeals for the First District. Details here; actual ruling here. And off it will go to the Supreme Court at some point in the not too far future. My lawyer friends tell me it’s very well argued and positively backed to the gills with a half century worth of precedent, which is a nice virtue for a ruling to have, especially if one is in philosophical agreement with it.
This is a slightly different issue than same-sex marriage, but it seems to me that if the Supreme Court agrees DOMA is unconstitutional then I don’t see how the constitutionality of banning same-sex marriage is sustainable in any sense. Which bothers me not in the slightest, of course.