Arduino is a great open-source physical computing platform based on a simple i/o board and a handy development environment that implements the Processing/Wiring language.

Download and install the arduino IDE. Simuino is a handy tool that allows you to simulate an Arduino board, so that you can test your Arduino code even if you don't have a physical board. Write an Arduino sketch to read morse code from a pin and write its out put to the serial interface. Use '.' (dot) / '-' (dash) sequences to display the character.

Useful Links

http://www.arduino.cc/

http://web.simuino.com/

http://en.wikipedia.org/wiki/Morse_code