Judge Nelson ruled in favor of the players injunction to end the lockout. She did not "stay" her decision, meaning its in effect immediately. The NFL will try to get a "stay" in court tomorrow, but for this evening the lockout is over.
I doubt any team starts signing people now, but technically they could. Perhaps we could get the Ngata deal done. Or people could trade players for picks in the draft. In fact it would have a huge effect on the draft if it remains in effect the rest of the week.