I would like to develop an app like Viber, WhatsApp or similar for iPhone, Android, Windows Phone, and possibly PC and Mac.
The app functions must include text, picture and video messaging across all platforms, with voice calling. The application's user interface shall include tab bar on the bottom giving access to messages, recent calls, contact, the keypad and a button for accessing more options. Upon installation, it should create a user account using one's phone number as username. Address book to synchronize with phone's address book so users do not need to add contacts in a separate book. All users must be registered with their phone number, the software returns all App users among one's contacts. Additional features include file sharing capability (photos, videos, audio, etc), location sharing, group chatting, user profile, possibility of syncing with facebook account, and potential for further upgrade. If possible Two versions of the app are required one with limited access to certain features and one version with full feature access.
Possibility of Multi-language platform for the above mentioned description. I need WeChat, Viber, MessageMe like application.