My favorite set of tutorials (I have not run the Cocoa Dev Central progression) was the O'Reilly tutorials at MacDevCenter. Scroll all the way to the bottom, and start working your way up. Of course, I never actually made it much past the 6th or 7th tutorial before I spun off on my own and started working on *my* project. That was all it took before Cocoa made sense, and I could start getting something out of Apple's documentation myself.