how to control gmaeobjects with a mouseclick

hi all, i would like someone to help me or point me in the right direction for making a script which will control a game object, like if i click on it , it follows my mouse until i click.

my current code is here…
var speed;

function OnMouseDown(){

transform.position = Vector3.MoveTowards(transform.position, MouseCursor.transform.position, .03);

}

This script might be of some use, not knowing how complex your needs are: unifycommunity.com

i know i don’t make my answers very informative, but your script doesn’t seem to work, it says it has no idea what desired movement means, and since i’am no expert at making games in c# i am lost…