It's not opensource. "Lightworks isn't Open Source yet, so external
programmers can't contribute to the core project right now, but I'm sure
the Lightworks team appreciate their offers and enthusiasm. Keep watching
RedShark for the latest on Lightworks."
Taken from here:
http://www.redsharknews.com/technology/item/512-lightworks-for-linux-first-…
I like the "yet" in there though.