This week's book giveaway is in the OO, Patterns, UML and Refactoring forum. We're giving away four copies of Refactoring for Software Design Smells: Managing Technical Debt and have Girish Suryanarayana, Ganesh Samarthyam & Tushar Sharma on-line! See this thread for details.
About memory management: On Mac OS, Obj-C has an (optional) garbage collector. iOS does not have a garbage collector, but something better is coming in iOS 5: ARC. ARC will automatically put instructions for retaining and releasing memory into your program when you compile it. So from a developer's perspective it's like garbage collection just with the big advantage that there's actually no garbage collector at runtime.