They have started the casting work for GL, they just haven't announced/signed anyone yet.
There were a lot of rumors last month that Chris Pine (Kirk in the new Trek movie) got the part of Hal Jordan, but he said last week
that while he did indeed meet with the casting director/producer, he hasn't agreed to anything nor has he even seen the script yet.
The GL movie is supposed to start shooting later this Fall in Australia. The director attached to the film at the moment is Martin Campbell (Casino Royale).
GL:First Flight looks awesome. I can handle them changing up some things (Abin Sur, Sinestro's timeline, etc) to create an "ultimates" type GL universe (like they changed some things to make Superman: Doomsday) as long as there is a good story...