Money Transfer from MSISDN to MSISDN

I want to develop an application where user can transfer can send money using mobile no somewhat like paypal, paypal user target email ids registered with paypal. For money transfer will use mobile payment gateway from 3rd party or suggest other option without payment gateway. Application will do one time registration and can manage bank a/c details so that once some transfers money will come directly to it. 1st step is for J2ME then Andriod, Blackberry & Iphone respectively. Let me know about timelines and best costing.