The catch is, your same-sex couple must possess a valid marriage certificate from another jurisdiction — one of the five states that recognizes same-sex marriages, or the District of Columbia, for instance — in order to qualify.
Not to shit on this parade further, but same-sex marriage is still prohibited my Maryland state law, which defines marriage as 1 Man + 1 Woman (the 4 Life bit is optional). Oh, and Don Dwyer, a Republican member of the House of Delegates who tried unsuccessfully to have our state attorney general impeached over his support for this policy, says he is considering suing the state over the extension of benefits to same-sex couples that were legally married elsewhere.
So, yeah. We still have a long way to go in Maryland yet. But this is still good news.