Don't fret about cross-platform. However, if you want to do games, look at Unity3D ($$) - that is cross-platform. I'm an iOS developer, now doing a deep-dive i

Don't fret about cross-platform. However, if you want to do games, look at Unity3D ($$) - that is cross-platform. I'm an iOS developer, now doing a deep-dive into Android. Pretty much, the consensus among my iOS developer circle is that to be considered a serious mobile player you need three platforms: iOS, Android, and mobile web. To be more marketable as a developer, there is no single platform that you want to learn (the true answer is to strive to become a better designer than coder - the best coder I know personally is a better designer - and that is one of the reasons he's had top-10 App Store apps). Learning Android has less of a learning curve. Knowing both iOS and Android is hard - I'm trying to do that now - and I've given up - shelved all my iOS projects to focus on Android. Android is going to win in the long-run. WebOS is going to be a footnote in the history of tablets (unfortunately Nokia didn't buy them 2 years ago). Windows Phone 7 is a wildcard. By mobile web, I don't mean rich HTML5 - I mean decent mobile optimized websites like http://shakeshack.com http://shakeshack.com If you are going to study iPhone, just dive right in. The analyzer will save you from the most egregious of memory leaks and retain cycles. You will realize that your code you are writing sucks three or four iterations or generations down the line. Don't fret about that. You will go back and forth between the benefits of IB vs writing code for UIs directly. If you are going to study Android, the code from OpenIntents is some of the best written I've seen so far [1]. A lot of the Android examples don't cover non-trivial stuff (like how do you have a ContentProvider that can handle multiple tables, how do you skin). OpenIntents shows a way, maybe not the best way - but decent, how to do all of that. [1] http://code.google.com/p/openintents/source/browse/trunk http://code.google.com/p/openintents/source/browse/trunk