I loved First Flight and am thrilled to see a return to that universe. This does mean, however, that Emerald Knights will differ from Gotham Knight in that it won't serve as a bridge between or tie-into the live action movies.
"Warner Home Video and DC Entertainment present the first official trailer for “Green Lantern: Emerald Knights,” the next direct to DVD feature in the DC Universe line of movies. “Green Lantern: Emerald Knights” stars Nathan Fillion, Elisabeth Moss, Henry Rollins, Jason Isaacs and Roddy Piper and is set for release on June 7, 2011."Source: CBR
I've also put the 'First Look' below, just incase you missed it: