box collider mouse over

Hi I made a house in Unity, and set a Box Collider to cover the house. What I want is when the user put cursor on the house, the house will change colour or something else, then the user will know this is a button to click. I have done the button part, click the house will take you to level 2, but I don't know how to make the rollOver and rollOut. Can you help please

function OnMouseUp(){ Application.LoadLevel(1); }

Thanks

Okay,

Its slightly more complicated than you would think. First off, create two new tags called 'Selected' and 'Unselected. Then use this script

var clicked : boolean = false;
var hit : RaycastHit;

function Update() {
    if(Input.GetMouseButtonDown(0) &&
       collider.Raycast(Camera.main.ScreenPointToRay(Input.mousePosition), hit,
                        Mathf.Infinity)) {
        clicked = !clicked;
        if(tag == "Selected") tag = "Unselected";
        else tag = "Selected";
        Debug.Log("clicked" + (clicked? "" : " off"));
    }
}

Once that is done, grab your house and tag it to 'Selected'. In the console you should see it saying 'clicked' -- ' clicked off'

So long as a gameobject has a collider attached to it, you can accomplish what you want with mouse events:

OnMouseOver

OnMouseExit

OnMouseEnter

No need to get complicated with your update; these events will fire asynchronously