[Farani]

There are two good books for mac programming... programming for the iphone is just an extension of that. I'm in the process of learning to program for the mac myself... I have a C++ background so I'm still learning the syntactical and logical differences between it and Objective-C. I've also only been on a mac for about a year so I'm learning XCode, too. Anywho...

"Programming in Objective-C" Stephen G. Kochan
There is going to be a "Programming in Objective-C 2.0" Comming out soon...

"Cocoa Programming for Mac OS X" THIRD EDITION by Aaron Hillegass.

There is going to be a specific book out by Erica Sadun on actually using the SDK to build iphone apps but it won't be out until October and she can't even talk about the book because of the NDA right now. But until then, those 2 books, and then reading through the frameworks are your best bet. Hope that helps!