Time to learn Objective-C/Cocoa for an Apple agnostic
This question is inevitably subjective, but I will ask anyway.

I'm a PC. I've always been a PC. I have very little Apple expertise, although I'm completely happy in *nix. I've plenty of experience with development, and consider that I am able to pick up new languages and concepts faster than most of my colleagues (although ML/F# still hurts me on a regular basis). I'm reasonably familiar with C++, although haven't touched it since the nineties, work on a daily basis, and 100% confident with C#,  would consider myself advanced to expert with Java and have developed a reasonable amount of stuff in Lisp and Prolog back in the day.

We've had a recent request to develop an iPhone app, which sounds like quite an interesting proposition that we'd be quite interested in taking on. We have very little in-house experience with Apple platforms. Given our ignorance of most things Apple, little to no familiarity with OSX and the Apple UI paradigms and assuming we acquire the necessary hardware for development:

1. What one would need to learn?
2. How long would a good developer need to get up to speed?
3. Are there any non-obvious expenses that might arise from pursuing this route?

Once again, apologies for the subjective nature of this question. Many thanks.
Time to learn Objective-C/Cocoa for an Apple agnostic
===

This question is inevitably subjective, but I will ask anyway.

I'm a PC. I've always been a PC. I have very little Apple expertise, although I'm completely happy in *nix. I've plenty of experience with development, and consider that I am able to pick up new languages and concepts faster than most of my colleagues (although ML/F# still hurts me on a regular basis). I'm reasonably familiar with C++, although haven't touched it since the nineties, work on a daily basis, and 100% confident with C#,  would consider myself advanced to expert with Java and have developed a reasonable amount of stuff in Lisp and Prolog back in the day.

We've had a recent request to develop an iPhone app, which sounds like quite an interesting proposition that we'd be quite interested in taking on. We have very little in-house experience with Apple platforms. Given our ignorance of most things Apple, little to no familiarity with OSX and the Apple UI paradigms and assuming we acquire the necessary hardware for development:

1. What one would need to learn?
2. How long would a good developer need to get up to speed?
3. Are there any non-obvious expenses that might arise from pursuing this route?

Once again, apologies for the subjective nature of this question. Many thanks.