[Mr_Rose]

OK, first: Fantastic news; this was basically the last thing stopping me from going Mac full-time, now that Steam is out for the Mac too.

Second: The dreaded licensing; how are these things going to be sold? Ideally, from a consumer perspective, I'd like to be able to buy a single license for "army builder" that covers all platforms; Mac, Windows iDevice, droid etc.
But I don't think the iTunes app store is particularly amenable to this, unfortunately.
On that basis, might I suggest that you have a "first platform" price and "additional platform" prices for each other app in the family and that these be one-off purchases?