help a noob with a fun halloween project, LED fade

Using Arduino Project Guidance
2

Use the PWM out pins, 3,5,6,9,10,11, and change the analogWrite value over time to create a fade:

/*
 Fading
 
 This example shows how to fade an LED using the analogWrite() function.
 
 The circuit:
 * LED attached from digital pin 9 to ground.
 
 Created 1 Nov 2008
 By David A. Mellis
 modified 30 Aug 2011
 By Tom Igoe
 
 http://arduino.cc/en/Tutorial/Fading
 
 This example code is in the public domain.
 
 */

int ledPin = 9;    // LED connected to digital pin 9


void setup()  { 
  // nothing happens in setup 
} 


void loop()  { 
  // fade in from min to max in increments of 5 points:
  for(int fadeValue = 0 ; fadeValue <= 255; fadeValue +=5) { 
    // sets the value (range from 0 to 255):
    analogWrite(ledPin, fadeValue);         
    // wait for 30 milliseconds to see the dimming effect    
    delay(30);                            
  } 


  // fade out from max to min in increments of 5 points:
  for(int fadeValue = 255 ; fadeValue >= 0; fadeValue -=5) { 
    // sets the value (range from 0 to 255):
    analogWrite(ledPin, fadeValue);         
    // wait for 30 milliseconds to see the dimming effect    
    delay(30);                            
  } 
}

Or you fake PWM with software if you need more than 6.