Can I read the loaded progam within a Pro Mini ?
Apearantly yes, …but not read it in the way that you wrote the sketch. Only as a hex file, containing the numbers that make up the (flash)memory of the arduino. Not as commands you can understand.
[Warning]! Improper use of avrdude might break your Arduino bootloader! Not advised for beginners.
http://forum.arduino.cc/index.php/topic,6150.0.html
Why do you need to read it? Or what do you want to do with the result?