I raised this one earlier (there is a thread but I can't find it) but I think the problem is not so much with TW but more that Apple iPhones don't run flash (yet)!
The topic has been discussed before : for the time being only single pano can be displayed on the iphone (pangea vr/cubeworld)
But even if the iphone was supporting flash (Window mobile 7 will not support flash either), a TW tour or any flash based tour would not run smoothly since the processor is just not made to handle such task as any smartphone. It would require a dedicated software which would really make a light tour, processor wise.