2D drag script Need Help!

Hello,
I am currently developing a game but I need help with something. Is there any script that allows you (the user) to click/tap on an object and drag it around? I am developing this for the I Phone so any help would be greatly apprenticed.

You should not ask people to write your code here. Rather, try to write your own and post the errors you might receive.
Here is an example script:

using UnityEngine;
using System.Collections;

[RequireComponent(typeof(BoxCollider))]

public class Drag : MonoBehaviour {
    private Vector3 screenPoint;
    private Vector3 offset;

void OnMouseDown() {

    offset = gameObject.transform.position - Camera.main.ScreenToWorldPoint(new Vector3(Input.mousePosition.x, Input.mousePosition.y, screenPoint.z));
}

void OnMouseDrag()
{
    Vector3 curScreenPoint = new Vector3(Input.mousePosition.x, Input.mousePosition.y, screenPoint.z);
    Vector3 curPosition = Camera.main.ScreenToWorldPoint(curScreenPoint) + offset;
    transform.position = curPosition;
}
}