The legislation says the president and his top military advisers must certify that lifting the ban won't hurt troops' fighting ability. After that, there's a 60-day waiting period for the military.So it doesn't go into effect immediately, though I hope the armed services put a moratorium on DADT discharges in the meantime.
It's one step forward, an important step. But in the words of a retweet, "Now give those brave gay soldiers someone to come home to: Legalize marriage equality."