Mobile Banking applet SMS support

I need a mobile application that I can load on any handheld phone or PDA and that sends and receives standard SMS messages in the background to/from my server. The messages contain balances for accounts, transaction reporting, funds transfers, payments of bills etc. My server supports incoming and outgoing sms messages for all of the required functionalities that I need the clien tot do. The application has to be able to encrypt the sms messages by using a pre-defined algorithm that I have. The application has to support free-form notifications from the server such as 'please come and pick-up your documents asap'.