We had to learn objective c for starters, and how to develop in XCode. I've never owned a mac (spending most of my time in Windows and Linux), so just getting around and getting used to OSX was a little uncomfortable. But, as a long time developer, I love to learn new languages and environments, so I welcomed the challenge. As I suspected OSX was a dream, and learning objective c wasn't too bad either. The biggest challenge coming from Java and C# was memory management, something I thought was firmly in my past.
With the fairly simple rules, and naming conventions present in the iphone development world, it wasn't nearly as bad as my memories of malloc() and free(). It still takes some thought though, and I welcome the time when GC is available on all platforms.
We're putting the finishing touches on our first game, and so far it's come out pretty good. We picked something fairly simple to start with. Coding the game itself, and working with a graphics artist to get us all the graphics needed might be the easy part. We are now in a private beta soliciting feedback from friends and family. After that it's time to rev up the marketing machine and get it submitted to Apple for approval.
Check back for more updates as we work through our first iphone application.