I follow below resources to learn how to develop iPhone application. It's a start, I try to keep notes what I learned during development. First, we just need a good book let you get start. you can find below resources to get that book. You can also buy traditional Chinese version. Just follow example to go over the steps, you will get familiar with it.
Object C in Traditional Chinese.
Object C material from apple.
Cocoa Dev Central
iPhone dev book web site, you can download sample code for free.
Stanford iPhone Application Development
For Xcode part, For a beginner, I suggest you to buy "Beginning iPhone 4 Development: Exploring the iOS SDK "