Today I learned about "instanceMethodSignatureForSelector: (SEL)aSelector". Guess what it does? It returns a pointer to the C function implementing the method used to respond to messages with aSelector which are sent to instances of the receiving class. It's all so clear to me now!
A lot to learn. More concrete accomplishments include building Subversion and Apache 2 from source, getting them to work with Xcode, and creating my first OpenGL application that contains a timer and responds to simple mouse-clicks. It's been a pretty interesting afternoon... This OpenGL, CGL, AGL, et cetera stuff really is a lot more complicated than I thought it was.