Jason over at Making Star Wars has posted the new Lucasfilm fanfare from the digital releases of the original and prequel trilogy, in place of the original 20th Century Fox fanfare (with CinemaScope extension) by Alfred Newman:
It’s basically an edited version of the final fanfare from The Empire Strikes Back.
Today there’s a lot of complaining, but I think this is a good compromise, and it’s something that’ll be with us for a while in any case. It’ll almost certainly be what we hear in front of The Force Awakens and Rogue One.
Note that the old fanfare is still before Star Wars: A New Hope—20th Century Fox own the rights to that film, not Lucasfilm (or Disney).