I'd like to write an application for any Sprint phone that automatically replies to all incoming SMS messages. That is, any time an SMS message arrives in the inbox, the application should send a reply back to the sender number.

WMA won't work because applications can only listen on particular ports and they only get messages bound for those ports. Additionally, it looks like there is no way to send the SMS automatically without any user intervention. As far as I can tell there are no Series 60 or Brew phones for Sprint.

Is there any way to do this at all?