Search wiring.org.co:

This example is for Wiring version 1.0 build 0100+. If you have a previous version, use the examples included with your software. If you see any errors or have comments, please let us know.

ServorFirmata
This firmware supports as many servos as possible using the Servo library TODO add message to configure minPulse/maxPulse/degrees This example code is in the public domain.

    #include <Servo.h>
    #include <Firmata.h>

    Servo servos[MAX_SERVOS];

    void analogWriteCallback(byte pin, int value)
    {
        if (IS_PIN_SERVO(pin)) {
            servos[PIN_TO_SERVO(pin)].write(value);
        }
    }

    void setup()
    {
        byte pin;

        Firmata.setFirmwareVersion(0, 2);
        Firmata.attach(ANALOG_MESSAGE, analogWriteCallback);

        for (pin=0; pin < TOTAL_PINS; pin++) {
            if (IS_PIN_SERVO(pin)) {
    	    servos[PIN_TO_SERVO(pin)].attach(PIN_TO_DIGITAL(pin));
            }
        }

        Firmata.begin(57600);
    }

    void loop()
    {
        while(Firmata.available())
            Firmata.processInput();
    }