How to make a "Pick Up" script?

Put this script onto your player object or camera:

 var Letter : GameObject;//leave empty, the script will assign it
 var Image : Texture2D;//leave empty, the script will assign it
 var ShowLetter : boolean;//don't touch :)
 var LetterMask : LayerMask;//select the layer of your letter object in this drop-down list
 var cam : Transform = Camera.main.transform;
 
 function Update()
 {
     var ray = Ray(cam.position, cam.forward);
     var hit : RaycastHit;//stores information about things we hit with our raycast
     
     if(Input.GetKeyDown(KeyCode.E))
     {
         if(ShowLetter == false)
         {
             if (Physics.Raycast (ray, hit, Mathf.Infinity, LetterMask))
             {
                 Letter = hit.collider.gameObject;//assigns the letter object that was hit by the raycast to this script's Letter variable so we can access it, should we want to pick it up.
                 Image = hit.collider.gameObject.GetComponent(LetterScript).LetterImage;//assign the LetterImage from the letter object that was hit to this script's Image variable so it can be accessed in OnGUI()
                 ShowLetter = true;
             }
         }
         else
         {
             ShowLetter = false;//if the letter image is already being shown, hide it again.
             //here, you could also make the player pick up the letter object by making it a child of himself:
             if(Letter != null)//just to be sure, check if the Letter variable isn't empty
             {
                 Letter.transform.parent = transform;//make the letter a child of the player so it stays with him. It's not really needed though.
                 Letter.transform.position = transform.position;//put the letter at our player's location.
                 Letter.renderer.enabled = false;//make to Letter object invisible, we don'T want to see it while carrying it, right?
                 Letter.collider.enabled = false;//disable the Letter object's collider, so it doesn't interfere with any raycasting we do.
             }
         }
     }
 }
 
 function OnGUI()
 {
     if(ShowLetter == true)
     {
         GUI.DrawTexture (Rect (Screen.width / 2 - Image.width / 2, Screen.height / 2 - Image.height / 2, Image.width, Image.height), Image);
     }
 
 }

And this mini script, called LetterScript, has to be attached to your letter gameobject: (be sure to drag an imaage to the LetterImage variable!)

 var LetterImage : Texture2D;