Well, like some people say, it will come down on availability. But if there is enough to be sold.
1) normal estimate: 100K optimistic: 150k
2) after E3 with some nice surprises by Sony (hopefully) WW 50k-70K
3) No, Wii is unstoppable, sales will only drop when there are enough available, it seems.
The Patapon forumtopic: http://www.vgchartz.com/forum/thread.php?id=14103