not exactly.. i want to upload the arduino gsm sketch by pressing a button (made on a breadboard with a little circuit or something) instead of pressing the "upload" button in the arduino program.
As I said, the Arduino is already listening for a new upload when you press the reset button. The problem is, that the connected PC has to be ready to send the new sketch. If not by pressing the upload button how do you expect the sketch to be uploaded is selected on the PC? Or better: How do you imagine the complete process from compiling the new sketch until it's stored in the Arduino's flash memory? If you describe that we may be able to tell you if your imagination is technically possible and maybe how it is possible.