I recently finished reading Randall Hyde's excellent book Write Great Code: Volume 1: Understanding the Machine, and I have a much better knowledge of what's going on under the hood now.
I want to start making iPhone apps, and there are lots of guides for that. Embracing my inner Hyde, however, I want to first learn about the iOS system architecture. Apple has a really good overview here:
Before I start, I wanted to know if there were any other good resources for understanding iOS architecture and using that knowledge for iPhone programming.