About high damn time if ya ask me. It just seemed "wrong" to be able to play this on PC (online and locally) and on XBLA without having something for iPhone. I suppose they wanted to make sure things were up to snuff rather than release some piece of garbage.
No mention about which countries this app will be available in (is the App store specific to particular countries like the iTunes store?).
Probably are geared towards countries. Some of the games and productivity apps aren't multilingual. It'd be difficult to use those programs without being able to read instructions on them.
Probably also for pricing too. As you mentioned with iTunes, the last I heard was one song download on iTunes in Great Britain costs 69 pences? That's about $1.29 USD, vs $1 what we pay in the US. I doubt the prices would be the same, even after converting the currencies.