Sorry, but it's not just "USA" and "the rest"
Europe/Japan is region 2, Europe uses (but for the french) PAL, Japan uses NTSC, so it has nothing to do with that. The regions were introduced by Hollywood to make sure the money flows like they want it, too. EG, usually Europe gets Movies and DVDs some months later and they do not want to change that really.
I seriously doubt that the Futurama DVDs are region 4 though... There would be no reason for that without FOX.au distributing them. (FOXhome.de/uk/au are competitors. It sounds stupid, but European DVD exports to au would be seen as stealing biz from Foxhome.au, even though it ends up in the same big pot in the end)