function simplePreload(args)
{
    document.imageArray = new Array(args.length);
    for(var i=0; i<args.length; i++)
    {
        document.imageArray[i] = new Image;
        document.imageArray[i].src = args[i];
    }
}

var preloadArgs = new Array('images/btns/about_us_over.gif', 'images/btns/contact_us_over.gif', 'images/btns/work_for_us_over.gif', 'images/btns/directions_over.gif');
simplePreload(preloadArgs);