Well Japan is pretty simple at least on getting a good guestimate. It's Europe and America that are really hard as you really don't know if it'll have a good opening week or just at title that sales its opening week over a course of 2-3 weeks and has good legs.
So Japan will be about 400k first week with some good legs. My guess on Europe is normally titles like that sell better on its second week which is kinda weird. But I would say 300k in Europe first week. And considering just how America and Wii are big right now I'll say around 600k for America. So:
Japan: 400k
Europe: 300k
America: 600k
Total 1st Wk: 1.3 million
Second week sales shouldn't drop off too much as the title should have decent legs considering the GC and DS versions. So I'd say second week will probably have around 700k-800k worldwide as well seeing minimal dropoff in Europe and only halving in Japan and America.
