Mathieu Tozer's Dev Blog

I got this book today! I've been getting through it - it's really good. Pg 96 already but I feel I am learning a lot. I like the way it's not all tutorials, not all theory. Not quite as heavy as the Apple documentation can sometimes be, and he sneaks in little boring bits here and there in between the fun stuff, so you barely notice.
And it wasn't prohibitively expensive either which is fantastic. 65 odd dollars at Borders.

Update:
I've used and understood about delegation from objects, and have a firm understanding about what happens in class structure in terms of where and how methods are called.
I'm regretting not stumbling upon this book earlier because it's really effective. Of course I won't know until I've finished it and find myself writing cocoa programs, using it as a reference, that it has been effective, but I'm confident!