I never get tired of telling people about the becomeanxcoder tutorial at
http://www.cocoalab.com/. It's slightly outdated, but you should be able to figure out the few differences and everything it teaches still applies. It assumes you don't know how to program, so anyone can use it. It teaches Obj-C and Cocoa, using Xcode and Interface Builder. Unfortunately it's not very long, I wish it continued but it's plenty enough for a starter.
Use Google, this forum, and whatever books and tutorials/resources you find and you'll be able to learn!