Write an Android / iphone application

Hello I'm trying to get some information about how much it might cost to make a sms button mobile application what it is instead of sending sms text to a phone number you can push a button that haves preselected text to a cellphone sms. i have a remote gsm system if i send a - a1 in text to the device it will turn on some stuff if i send a a2 to that device it shuts off that device looking for a application instead of typing in the preselected text i can push 1 button that sends the a1 or a2 signal to that device in sms. i have google talk under josephchrzempiec if i can't be reached in here Joseph