Camera.WorldToScreenPoint

function WorldToScreenPoint (position : Vector3) : Vector3

Description

Transforms position from world space into screen space.

Screenspace is defined in pixels. The bottom-left of the screen is (0,0); the right-top is (pixelWidth,pixelHeight). The z position is in world units from the camera.

JavaScript
    var target : Transform;
function Update () {
var screenPos : Vector3 = camera.WorldToScreenPoint (target.position);
print ("target is " + screenPos.x + " pixels from the left");
}

using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
public Transform target;
void Update() {
Vector3 screenPos = camera.WorldToScreenPoint(target.position);
print("target is " + screenPos.x + " pixels from the left");
}
}

import UnityEngine
import System.Collections

class example(MonoBehaviour):

public target as Transform

def Update():
screenPos as Vector3 = camera.WorldToScreenPoint(target.position)
print((('target is ' + screenPos.x) + ' pixels from the left'))