A method for enabling transactions on networks that deliver services to users includes communicating a transaction application and a respective user identifier to a mobile communication device via a wireless connection. A set of complementary modules is stored, remote from the mobile communication device. When one of the complementary module has been loaded on the user's mobile communication device, it enables the user of the device to specialize a transaction on at least one of the associated networks by selecting at least one variable of the transaction. Different complementary modules can be provided to the user's mobile communication device for specializing transactions on other service provider networks.