JSONModel with Objective C Tutorials

Try AppCoda, or raywenderlich. For more specific to your question, here is a good tutorial: jsonMobil and Objective-c

If you really want to learn and understand Objective c, then you should definitely get the big nerd ranch book. It's really helpful.

After you finish that book, or once you have a base understanding of Objective-c, then have a look at this video: Stanford - ios 7, or for the newer apple language - swift, watch this: stanford - ios 8

These types of questions shouldn't be asked on Stackoverflow. You can try a site like Quora. They probably already have an answer for this.