I am not an object oriented programmer, but if I was I would take Stanford's free course on how to develop apps for the Apple iPad / iTouch / iPhone environment. Given the huge uptake on this technology, I did watch the 1st session of the Stanford course which gives a techie like me an understanding of the Apple iOS. Starting at 16:41 of the first lecture, the course gives a quick overview of how Apple's development system is constructed. This course is just one example of iTunesU!
I've added this course link to my Engineering Learning Portal Software Engineering Section.
However, if Apple is not your cup of tea (or fruit), then spend some time reviewing Google's long list of software engineering research. You may read / download the abstracts or the full papers. As with the Apple course, I've added this content to my Software Engineering Section and Manuals Section of the Engineering Learning Portal.