What are some good resources for learning Objective-C?

Question

I've been using Objective-C for about 6 months, and have a good grasp on the basic concepts. What are some resources (websites, PDFs, Books, Blogs, etc) to advance past this level?

Answer 1

I personally use http://cocoadev.com/ on a daily bases. Their Wiki is invaluable to me. Also http://www.macdevcenter.com/ is a good general Mac OS development resource. And finally http://cocoadevcentral.com/ has very niche examples and great beginner tutorials.

Answer 2

http://stackoverflow.com/questions/7571/cocoa-and-objective-c-resources#8064

This is a duplicate question

Answer 3

The conceptual documentation at http://developer.apple.com is a good way to learn about the Cocoa APIs and the way they work, and there are some good mini-tutorials from GNUstep on doing particular things: http://www.gnustep.it/nicola/Tutorials/