Update: Look everybody! Ron Gilbert stopped by to post some details and answer your questions! Thanks, Ronzo!
Since Apple doesn't have a proper way to do beta testing, iOS games are often released in one country to gather information and feedback, so that's what we did with The Big Big Castle and it's worked very well.
We've made a bunch of changes and with any luck I'll be submitting a new build to the App Store Sunday night, so it should be available world wide in a week.
As far as Android goes, yeah, I'd love to support Android but there are a couple of issues.
The first is that I love objective-c. It's one of the best (and most fun to program in) languages I've ever seen. While it is true you can compile obj-c code for an Android device, the big missing piece is the NextStep libraries that Apple uses. Google needs to create an official and robust set of xcode libraries that use OpenStep and make it easy to cross build apps. I know a lot of iOS devs that use objective-c and don't want to (or can't) write their game twice. If Google would do this, there would be twice as many games on Android.
The other big (and most important) issue is that this game (and the 10 other ones Clayton and I have built but never released) are just weekend side projects we work on for fun that have nothing to do with Double Fine or The Cave. We just do them to relax.
Update 2: It's now available on the US Appstore and the NZ Appstore as well. Ron has also posted some more about it's development at his Grumpy Gamer blog.