Great write-up on the new features in the excellent Xcode 3.2. It has already made my life 100% better since I upgraded to Leopard. If you're not on it, you're missing out. This article tells you exactly what you're missing out on :)
Seasoned Objective-C developers are accustomed to certain ways of subclassing objects. While we definitely subclass objects less often than developers of other languages, it is still necessary in many cases.