xD This probably would do better in the Square-Enix subforum, since it is a Square-Enix question.
Anywho, the new version of One-Winged Angel is performed by the Black Mages, and even features new lyrics.
Unfortunately, it hasn't been released. Even on the More Friends Concert CD (which is another place it was played) it wasn't one of the songs on the tracklist.
So unless you're attending a "More Friends" concert, the only other place to hear it is in the trailer.