How can I control outputs on an Arduino board by inputs from a keyboard that is transmitted through the USB connection of the board?
I guess that I need some type of software that can take the keyboard inputs and convert them to the appropriate signals that the arduino can handle, but so far I haven’t found anything…
This control method is just one of the alternatives that I am considering, any other communication method you may think of could be helpful 
What about connecting a serial to the serial port on the arduino that communicates with an appropriate program? If I am correct in my assumption that I can program the arduino to receive strings or integers and use these commands to control the PWM outputs, then it should work. I am a newbie on microcontrollers so this might not be the case…
Bad choice of words… It just meant connecting a serial cable between the PC and the serial port on the arduino 
My plan now is to use HyperTerminal or PuTTY to send commands to the u-controller.
Consider a USB Host Shield (the USB plug is more appropriate to a USB keyboard). You would of course need to write your own code to decipher the output from the keyboard and use it accordingly.
Hope this helps,
You can communicate serially via the USB port or the Tx / Rx pins on the Arduino. The choice of keyboard will determine how you connect it to the microcontroller. Not sure what you meant when you said “connect a serial to the serial port”.
