Developing plugins for iphone

I’d like to start researching how plugins are developed for ios and unity. Are there any tutorials around that anybody can recommend?

Specifically I am interested in learning how things like webkit are integrated into unity.
What sort of books, tutorials would be helpful for taking on a project like that coming from the background of someone who has been developing in unity using javascript for 4 years.

Thanks,

Plugins on iOS essentially means writing ObjectiveC code that can call into the Apple APIs. If you want to start extending you iOS projects to do things that Unity doesn’t (yet) support, then learning ObjectiveC and Cocoa is your best bet, and there are many books about that. If (conceptually) you set yourself the target of writing a small iOS application that does not use Unity at all, then you’ll be on the right track.