Hi lickey,
sorry for the long silence.
It's the first time I'm reading AnalogInOutSerial ... so the response is based only on the code you posted.
int sensorValue = 1.024; is non important, you reset in the beginning of loop() with sensorValue = analogRead(analogInPin);
And Arduino is reading. So it reads values 0 - 1023 and you would map to 0 - 255: map(sensorValue, 0, 999, 0, 255);