Judge Susan Nelson reportedly ruled in favor of the NFL Players and ordered the NFL to lift the lockout according to an ESPN report. The owners are expected to file an appeal. This turn of events has been widely speculated for the past few weeks since Judge Nelson held her first hearing in the case.
A group of NFL players filed suit against the NFL claiming that the owners were acting in violation of anti-trust laws. The decertification of the NFLPA as the official union authorized to bargain with the league's owners opened up the door to the law suit.
Before NFL fans start celebrating Monday's ruling, there's a very good chance that an appeals court will order things held in place until further hearings are held. That would mean the lockout would continue. There is, however, a chance that won't happen in which case we would likely see chaos. Without a collective bargaining agreement in place, individual teams would be free to negotiate with individual players with no limitations. There would be no salary cap and all the rules covering the NFL's interactions with the players would no longer exists.
Since neither side really wants that kind of confusion, this is most likely just another step in the long process that will eventually, some day, lead to a negotiated settlement between the NFL's players and owners.