These are some of the better blogs and authors in my Google Reader related to iOS, Cocoa, and Objective-c:
“iPhone Development” – Jeff LaMarche : Always well written and in depth articles. Virtually every article gets starred in Google Reader.
“Cocoa with Love” – Matt Gallagher : If you’re looking for how to use an obscure part of the apple frameworks, this would be the first place to look. Usually Matt’s posts come with accompanying sample code.
“Able Pear Software” : A lot of good beginner articles. Not updated as frequently as it used to be, but their twitter feed has been very active with links to resources.
“Dr. Touch” : Another resource for finding information on lower level or more obscure cocoa tips.
“Cocoa Is My Girlfriend” : Real world coding examples
“iCodeBlog” : Tips and help from a variety of authors