From The DC Comics Retailer Roadshow Report
There’s also another Green Lantern event in the works titled Lights Out in October. He also touched on the crossovers that will be happening from the Zero Year arc in Batman. Didio informed retailers that these stories were not manufactured as crossover titles just for the sake of crossing over and spreading out the success of Batman, but that these writers and creators had expressed a genuine interest in writing a story that occurs at the same time as Zero Year. It seems there will be crossovers in Action Comics, Flash, Green Arrow, Green Lantern Corps, Batgirl, Nightwing, Batwing, Catwoman, Detective Comics, and Birds of Prey.