Having written Cocoa apps in the past probably makes a huge difference. They did make the DRM work somewhat better later - I actually started trying to develop the instant they made the SDK available so initially I was one of a huge number of people complaining about cryptic error messages and complex instructions that didn't work at all. They later replaced it with messages that were sometimes helpful and instructions that sometimes worked.

I tend to have a "knack" for breaking software - which is why I've done QA for a lot of my career. It's clear there exist people who got the iPhone DRM to work once and it just kept working after that; I don't know how they managed it or what if anything I did differently. As a workaround, I eventually got in the habit of treating the iPhone SDK much the way people used to treat word processors back in the day. That is: save often and make frequent backup copies of the whole project. When your project stops working for some mysterious reason, go back to the previous version that did work. In short, I applied "cargo cult" programming techniques.

I did ultimately manage to put an app in the iPhone store but that experience soured me on further iPhone development. Though I might try using Corona sometime.

That makes sense, a year or so of progress makes all the difference to a development environment. And yes, knowing a bit of desktop Cocoa makes it much easier to get into, but I didn't have much of a problem learning Cocoa once I found Hillegass' book.

Corona looks interesting. I could make fun of the spelling mistake on their home page though.