I think they'll put it for free on Leopard, as they did with Panther having iLife 04 loaded on it for free. Nowadays most Apple system requirements is 10.3.9 or higher, but with iLife 07 I think it'll be 10.4 or higher, so this might again be a way of forcing people to upgrade from Panther to Tiger, so they can have iLife 07. But maybe I'm all wrong... we'll have to wait and see how it ends up as.