I enjoyed the Cocoa intro (especially that it went into TDD, which I've never seen before) and I look forward to more advanced ones to come. In particular, I'd like to see something about more advanced things like Core Data, Cocoa Bindings, and anything that's done through Interface Builder or other GUI development tools. (Profiling with Instruments might be good too, depending on time.)

Reading articles about these are painful because they're really hard to describe (select Foo from the dropbox in the upper left, uncheck 2 or 3 boxes, etc). I think PeepCode would be the ideal format for these topics.