I taught myself from the NeXT documentation many years ago.
The book I used, 'Object oriented programming and the objective-C
language', can be found online at http://objc.toodarkpark.net/
I've read that doc before, even though it helped me to read ObjC source, I still woulnd't know where to start writing anything! I'm the type of person that learns by example, and then trying it on my own, which Kochan does in "Programming in C" and the ObjC counter part seems to do the same.
Any feelings on the OS X book? From what I've read the Kochan book goes into some Foundation stuff, but the Cocoa Programming for MacOS X seems to go deeper. Some reviews also suggest "Cocoa Programming".
Stefan