how to get a enemy to spawn

I need a script were the enemy spawns every 2 minutes how do I do this

var startTime : float;
var enemy : Transform; //Your enemy prefab

function Update()
{
    if (startTime == 0) //New time
    {
        startTime = Time.time; //Set the current time
    }
    else
    {
        if ((Time.time - startTime) == 120) //Check if 120 seconds have passed
        {
            startTime = 0; //Set the starttime back to 0
            Instantiate (enemy, Vector3(0,0,0), Quaternion.identity); //Create an enemy (transform, position, rotation)
        }
    }
}

Or using the following method:

function Awake()
{
    InvokeRepeating("spawnEnemy",0,120);
}

function spawnEnemy
{
    Instantiate (enemy, Vector3(0,0,0), Quaternion.identity); //Create an enemy (transform, position, rotation)
}

Thanks for the great code… however there is a small bug. The line

if ((Time.time - startTime) == 120) //Check if 120 seconds have passed

should be changed to:
if ((Time.time - startTime) >= 120) //Check if 120 seconds have passed

This is because the test will usually fail since the difference is unlikely to ever be EXACTLY 120

; )