As Beppo mentioned elsewhere, DC will be publishing a new,
post-Infinite Crisis origin - as a multi-title three-part storyline - in a few months.
My understanding is that it's not a new origin. It's a telling of Kal-L's life story.
I must say, I had no idea that Kal-L would have such a major role in
IC -- let alone that he'd take over the Superman titles for a month -- and
JSA for, what, six months? I'm pleasantly surprised.