Automatic SMS content delivery system

The projecct will send sms or any other type of packet/data with pre-registered consent by the user, but prior to point of termination. I am conducting a feasability study on the technology. If you believe that you can make this type of delivery system happen LEGALLY and have it work across carriers, please respond asap.? Let me clarify the description of the application thoroughly: The USER will send an SMS to a service that initiates a service. ***THIS IS A VERY EASY FUNCTIONALITY, NOT DIFFICULT*** If a user is CALLED or is sent an SMS to, then the service FOR THAT USER is automatically activated, WITHOUT the user doing anything. The 'service' has to be notified that the USER has been called or sms'ed automatically without the USER sending a sms to the service. ***THIS IS THE CHALLENGE**** Is this application FEASIBLE without obtaining access to the wireless carrier network. IF there is more action required by the user such as pre-registration on a website, it can be done. the KEY is that the USER does not have to ''sms'' the service when the phone is called or SMS'd.? Please let me know.