int potpin = 0; 
int val,val1,val2,val3;   

void setup() {
  pinMode(9,OUTPUT);
  pinMode(10,OUTPUT);
  pinMode(11,OUTPUT);  
}

void loop() {
  val = analogRead(potpin);            // reads the value of the potentiometer (value between 0 and 1023)
  val1 = map(val, 0, 1023, 0, 255);     // scale it to use it with the LED (value between 0 and 255)
   val2 = map(val, 0, 1023, 255, 0);
   val3 = map(val, 0, 1023, 0, 200);
   analogWrite(9, val1 );
   analogWrite(10, val2 );
   analogWrite(11, val3 );                  
 }