Serial.Write Help!

here is my dimmer control. I just dont know where i should be putting the serial write command within the code, i am frankly very new to the actual coding side of the arduino. Any help or adjustments would be great. thanks!

/*
AC Light Control

Updated by Robert Twomey

Changed zero-crossing detection to look for RISING edge rather
than falling. (originally it was only chopping the negative half
of the AC wave form).

Also changed the dim_check() to turn on the Triac, leaving it on
until the zero_cross_detect() turns it off.

Attach AC_PIN output to optotriac input on circuit board.
Attach Zero Cross Detector output (on circuit board) to Pin 2 (interrupt 0)
optional LED to pin 3
Attach arduino GND to GND.
Attach arduino +5 to +5V.

Attach AC Hot (120v) to AC Hot wire on circuit board.
Attach AC Neutral to AC Neutral wire on circuit board.

Attach one wire from bulb to Bulb 1 on circuit board.
Attach other wire from bulb to Bulb 2 on circuit board (also AC neutral)

details here: http://wiki.dxarts.washington.edu/groups/general/wiki/4dd69/AC_Dimmer_Circuit.html

Thanks to http://www.andrewkilpatrick.org/blog/?page_id=445
and http://www.hoelscher-hi.de/hendrik/english/dimmer.htm

*/
int dim2 = 0;
unsigned char serIn;

#include // Avaiable from http://www.arduino.cc/playground/Code/Timer1

volatile int i=0; // Variable to use as a counter
volatile boolean zero_cross=0; // Boolean to store a "switch" to tell us if we have crossed zero
int AC_pin = 10; // Output to Opto Triac
int POT_pin = 0; // Pot for testing the dimming
int LED = 3; // LED for testing
int dim = 0; // Dimming level (0-128) 0 = on, 128 = 0ff
int freqStep = 65; // Set the delay for the frequency of power (65 for 60Hz, 78 for 50Hz) per step (using 128 steps)
// freqStep may need some adjustment depending on your power the formula
// you need to us is (500000/AC_freq)/NumSteps = freqStep
// You could also write a seperate function to determine the freq

void setup() { // Begin setup
pinMode(AC_pin, OUTPUT); // Set the Triac pin as output
pinMode(LED, OUTPUT); // Set the LED pin as output
attachInterrupt(0, zero_cross_detect, RISING); // Attach an Interupt to Pin 2 (interupt 0) for Zero Cross Detection
Timer1.initialize(freqStep); // Initialize TimerOne library for the freq we need
Timer1.attachInterrupt(dim_check, freqStep);
Serial.begin(19200);
// Use the TimerOne Library to attach an interrupt
// to the function we use to check to see if it is
// the right time to fire the triac. This function
// will now run every freqStep in microseconds.
}

void zero_cross_detect() {
zero_cross = true; // set the boolean to true to tell our dimming function that a zero cross has occured
i=0;
digitalWrite(AC_pin, LOW);
}

// Function will fire the triac at the proper time
void dim_check() {
if(zero_cross == true) {
if(i>=dim) {
digitalWrite(AC_pin, HIGH);
i=0;
zero_cross = false;
}
else {
i++;
}
}
}

void loop() {
serReadInt();
dim = constrain(dim2, 0, 120);
analogWrite(LED, dim);
Serial.println(dim2);

}

int serReadInt()
{
int i, serAva; // i is a counter, serAva hold number of serial available
char inputBytes [7]; // Array hold input bytes
char * inputBytesPtr = &inputBytes[0]; // Pointer to the first element of the array

if (Serial.available()>0) // Check to see if there are any serial input
{
delay(3); // Delay for terminal to finish transmitted
// 5mS work great for 9600 baud (increase this number for slower baud)
serAva = Serial.available(); // Read number of input bytes
for (i=0; i
inputBytes[i] = Serial.read();
inputBytes[i] = ''; // Put NULL character at the end
dim2 = atoi(inputBytesPtr); // Call atoi function and return result
Serial.println(dim2);
}
else
return -1; // Return -1 if there is no input
}