I just got a copy of Objective-C 2.0 Guide de Survie, a book written by Pejvan Beigui and published by Pearson. This 240 pages pocket sized book looks great for french speaking people coming to Objective-C (and I can tell you there are a lot of them since Apple released an SDK for that phone whose name I’ve forgotten). The book is also aimed at current Objective-C developers transitioning to Objective-C 2.0 as there is a whole chapter dedicated to that subject.
With this book, Pejvan comes back to its Cocoa roots. A number of french developers will remember him, as he has been very active in the early years of Mac OS X both as a member of Apple Developer Relations and as a founder of the Cocoa enthusiasts community Project:Omega (incidentally, he was the french translator for the original O’Reilly F-Script articles series). In the book, he makes approaching Objective-C 2.0 easier for people coming from other languages by often comparing its syntax and functionalities to those of Java and C# (with a little bit of Python too). He also puts emphasis on code quality, with advices on dealing with errors, assertions and unit tests.