This may be incorrect, but I wrote down that Aaron Hillegas (of Big Nerd Ranch) will have a new book out in May on Cocoa Programming for MacOS X. I'd imagine the top names will be having books out by next month. Amazon etc usually show the titles before they're published, with expected shipping dates, so you might want to find some good names of people in the area, then amazon search them for new material. Hope this helps
Kochan I imagine has something in the pipeline too.
Edit: And look, Monkaay has a Tutorial Directory At iPhone Dev SDK just put on today