The delay is apparently the result of director Baz Luhrmann needing some extra time to polish the film. He brought everyone back for some pick-up shots, which explains the paparazzi shots I've seen of Hugh Jackman riding around Oz in full drover gear. I thought he just did that sort of thing all the time.
The fact that Australia's delay means it now neatly dodges the release of Quantum of Solace is, I'm sure, mere coincidence. I suspect we'll see more November rearranging -- Variety is reporting that The Time Traveler's Wife is also coming out on the 26th, though IMDB is still showing a Christmas release. If Variety is right (and why wouldn't it be?), I wouldn't be surprised if it ran to the 14th to steer clear of competing with another romance. Plus, I just don't think America could handle Viggo Mortensen, Hugh Jackman, and Eric Bana all having a movie out on the same day -- not when us girls are supposed to be home making pumpkin pies and turkey.