Methods and systems for distributing a mobile device application for use in making and receiving payments utilizing a mobile device such as a mobile telephone (cellphone) or wireless connected personal digital assistant (PDA). A downloadable mobile device application, when installed on a compatible mobile device, is operative for communicating with a mobile financial transaction system (MFTS) that facilitates the making and receiving of payments via wireless mobile devices. The downloadable mobile device application is provided via a download system that downloads the application to mobile devices according to download procedures appropriate for a particular type of mobile device. When a payment is made to a payee having a mobile device, system communicates a message to the payee's mobile device that informs that a payment has been made and instructs the payee about the downloadable mobile device application. If the mobile device user/payee downloads and installs the mobile device application on his or her mobile device and provides enrollment information, interaction between the MFTS and the mobile device user/payee is permitted, and payment is provided to the mobile device user as user/payee.