Look at this post, http://arduino.cc/forum/index.php/topic,137352.30.html it does work and it compiles. Tweak it for your needs.
There are two codes, the one by dcr_inc will only display the numbers once " * " is pressed, and the one I corrected will display the numbers every time a button is pressed.
Keep in mind that they both use the LCD, so just fix it so that it goes to the serial monitor.