jQuery.fn.labelOver = function(overClass) {
    return this.each(function() {
        var label = jQuery(this);
        var f = label.attr('for');
        if (f) {
            var input = jQuery('#' + f);

            this.hide = function() {
                label.css({ textIndent: -10000 })
            }

            this.show = function() {
                if (input.val() == '') label.css({ textIndent: 0 })
            }

            // handlers
            input.focus(this.hide);
            input.blur(this.show);
            label.addClass(overClass).click(function() { input.focus() });

            if (input.val() != '') this.hide();
        }
    })
}

$(function() {
    $('label.pre').labelOver('over');
})