there is some good servo code here:
http://todbot.com/arduino/sketches/servo_serial_simple/servo_serial_simple.pde
That is really good code.. Tom Igoe and Jeff Gray wrote it originally, then I adapted it, then Todbot adapted it, and now it's your turn!
Not sure about the best way to do the keyboard interfacing...
For speed I would use Max/MSP or PD.
D