IsA: I recommend you to start with some concepts pictures of your GUI design and present them in this thread. I know we have Obj-C-Coders in our community, hopefully one of them wants to work with you on this project.
I'll try to assist you as good as I can, but I don't know Obj-C myself and currently I'm busy working on Italian morphology and plain C ( bad combination, but C is the requirement ...

). Anyway, don't hesitate to ask me if I can help you.