A method for providing mobile services, such as mobile financial services, includes providing a wireless handset or other device as an adjunct access device for a user account. The device is assigned a unique identification number, such as an MDN, MEID, or both. The unique identification number is associated with the account and in an exemplary embodiment, comprises at least a portion of the account number(s) with the service provider. Transactions are conducted with the handset access device and enhanced multi-factor and biometric security authentication may be provided. Handset voice, data, or other usage is settled and billed within the financial account. The service provider is able to download software, advertising, or content applications to the adjunct device and maintains the capability to disable the device. In a further aspect, a system for the execution of mobile transactions is provided.