In-Field Labels is a simple jQuery plugin that turns properly formatted HTML forms into forms with in-field label support. Labels fade when the field is focussed and disappear when text entry begins. Clearing a field brings back the label.
A jQuery plugin to help implement the over label technique. When the user puts focus on the input, the label will be hidden. When the input is blurred and has no value, the label will be shown again. Just need to write the CSS based on your DOM structure to position the label over the element correctly.