Using the Action Delegate and it's pretty sweet!

ActionTest.cs

using UnityEngine;
using System;
using System.Collections;

public class ActionTest : MonoBehaviour {

	// Use this for initialization
	private void Awake () {
		string url = "http://google.com";
		StartCoroutine(WaitForRequest(url,(status)=>{
			print(status.ToString());
		}));
	}
	
	private IEnumerator WaitForRequest(string url,Action<int> callback)
	{
		WWW www = new WWW(url);
		int tempInt = 0;
		yield return www;
		if (string.IsNullOrEmpty(www.error))
		{
			if(!string.IsNullOrEmpty(www.text))
			{
				
				tempInt = 3;
			}
			else
			{
				tempInt=2;
			}
		} else {
			print(www.error);
			tempInt=1;
		}
		callback(tempInt);
	}
}