Opposite to CodeAcademy, some courses are not free, you must pay, but there are several free interesting courses, so I encourage you to have a look, and if you’re interested, sign in, and of course, write me a comment with your experience!
Learning Objective C
I am not an Apple fan, mainly because I never tried one of their products, but I have several friends that are. Apart from my position, I am aware the Apple influence is big, and behind this products appears Objective-C, the native Apple language. I have no idea at all about Objective C, but if you are interested, the course at Code School http://www.codeschool.com/courses/try-objective-c, is a good atarting point to develop for Apple devices, like iPhone or iPad.
I hope It can be useful for you!