Simple Chat iPhone app

I'm looking for iPhone/iPad developer. The app is simple chat application talks only to our backend XMPP server. Functions and look and feel of this app is basically same as whatsapp(which is SMS app) but we'd like to change the chatting UI. Not just simple balloon, we need to add more emoji and background pictures by using XML format The app is to work on iPad and iPhone. In-App purchase is to be included in this app as well as iAd. iPhone Apps development experience needed.