Here is some code I have used, for reading four pots with Arduino:

Processing code:
//
/*  
Serial Call and Response in ASCII
Language: Processing

Reads in a string of characters from a serial port until
it gets a linefeed (ASCII 10).  Then splits the string into
sections separated by commas. Then converts the sections to ints,
and prints them out.

created 2 Jun 2005
modified 14 Apr 2009
by Tom Igoe
*/

import processing.serial.*;     // import the Processing serial library
Serial myPort;                  // The serial port

float fgcolor;                  // Fill color
float xpos, ypos;              // Starting position of the ball
float _alpha;
//int[] sensors = new int[4];

void setup() {
 size(640,480);

 // List all the available serial ports
 println(Serial.list());

 // I know that the first port in the serial list on my mac
 // is always my  Arduino module, so I open Serial.list()[0].
 // Change the 0 to the appropriate number of the serial port
 // that your microcontroller is attached to.
 myPort = new Serial(this, Serial.list()[0], 9600);

 // read bytes into a buffer until you get a linefeed (ASCII 10):
 myPort.bufferUntil('\n');

 // draw with smooth edges:
 smooth();
 noStroke();
}

void draw() {
 background(127,100,100);
 fill(fgcolor, _alpha);
 // Draw the shape
 ellipse(xpos, ypos, fgcolor, fgcolor);
}

// serialEvent  method is run automatically by the Processing applet
// whenever the buffer reaches the  byte value set in the bufferUntil()
// method in the setup():

void serialEvent(Serial myPort) {
 // read the serial buffer:
 String myString = myPort.readStringUntil('\n');
 // if you got any bytes other than the linefeed:
 myString = trim(myString);

 // split the string at the commas
 // and convert the sections into integers:
 int sensors[] = int(split(myString, ','));
 // print out the values you got:
 /* for (int sensorNum = 0; sensorNum < sensors.length; sensorNum++) {
  print("Sensor " + sensorNum + ": " + sensors[sensorNum] + "\t\t\t");
  }*/
 // add a linefeed after all the sensor values are printed:
 ///  println();
 if (sensors.length == 4) {
   sensA = sensors[0];
   sensB= map(sensors[1], 0,255,0,width);
   sensC = map(sensors[2], 0,255,0,height);
   sensD = sensors[3];

 }
 // send a byte to ask for more data:
 myPort.write("A");
}

// Arduino code:
int firstSensor = 0;    // first analog sensor
int secondSensor = 0;   // second analog sensor
int thirdSensor = 0;    // digital sensor
int fourthSensor = 0;
int inByte = 0;         // incoming serial byte

void setup()
{
 // start serial port at 9600 bps:
 Serial.begin(9600);
establishContact();  // send a byte to establish contact until receiver responds
}

void loop()
{
 // if we get a valid byte, read analog ins:
 // i.e. 'handshaking' ??
 
   if (Serial.available() > 0) {
     
   //   get incoming byte: why??
   inByte = Serial.read(); // not used for anything, is it?
   //   read first analog input, divide by 4 to make the range 0-255:
   firstSensor = analogRead(0)/4;
   //   delay 10ms to let the ADC recover:
   delay(10);
   //   read second analog input, divide by 4 to make the range 0-255:
 secondSensor = analogRead(1)/4;
   //   delay 10ms to let the ADC recover:
  delay(10);

    thirdSensor = analogRead(2)/4;  
    delay(10);
   
    fourthSensor = analogRead(3)/4;
    delay(10);
    // send sensor values:

   Serial.print(firstSensor, DEC);
   Serial.print(",");
   Serial.print(secondSensor, DEC);
   Serial.print(",");
    Serial.print(thirdSensor, DEC);
    Serial.print(",");
    Serial.println(fourthSensor, DEC);
   
 }
}

void establishContact() {
 while (Serial.available() <= 0) {
   Serial.println("0,0,0,0");   // send an initial string (determining the length of the sensors array!
   delay(300);
 }
}