Hi,
I have experience in iOS apps handling json data, i will put comments in the source code to give you the ability to edit in the future and understand what I am doing. you can see one of my previous apps in iTunes (Irish Golf) I am also working on a bigger product (Property Contrax, for iPad).
I am involved in a new tech start-up and have only just started looking around for freelance work, hence no real feedback.
If you have any questions let me know.
From my personal experience I would advise you to engage someone who is a native english speaker ( weather or not that is me) it can be very difficult to converse in a technical way otherwise. Best of luck, Niall