Thanks for your interest in finding out more about the Wikipedia iPhone app.
The current version of the app is very elementary and we are working on improving it.
If you have any feedback or need any help, please send an email to The Mobile Wikipedia Feedback Team. We'll get back to you ASAP.
Development is currently done in a mix of Objective-C, Ruby, and HTML5/JS. If you have experience in any of these, you should be just fine. The application needs a pretty thorough re-write at this time, more than it needs a new feature. Either going with a more pure HTML5/JS kind of setup, or doing Objective-C and becoming more of a native application.
You need to get the two repos from here: Wikimedia on Github
Please send any development questions to the Mobile Wikipedia List or visit us on irc.freenode.net in #wikimedia-mobile.