CODE
/read analog data instructables.com
import processing.serial.*;
import cc.arduino.*;

Arduino arduino; //creates arduino object

color back = color(64, 218, 255); //variables for the 2 colors

int sensor= 0;
int read;

float value;

void setup() {
size(800, 600);
arduino = new Arduino(this, Arduino.list()[0], 57600); //sets up arduino
arduino.pinMode(sensor, Arduino.INPUT);//setup pins to be input (A0 =0?)

background(back);
}

void draw() {
read=arduino.analogRead(sensor);
background(back);
println (read);
value=map(read, 0, 500, -200, width*4); //use to callibrate
ellipse(value, 300,30, 30);
}