vTip is designed to quickly provide very lightweight (0.7KB js, 0.2K CSS) tooltips to users of jQuery, for quick and appealing tooltips on any element.
<a href="http://www.vertigo-project.com" title="This is an example of a link tooltip." class="vtip">Link Tooltip</a>
<img src="http://www.vertigo-project.com/vertigo.png" title="This is an image!" class="vtip" />
<div class="vtip" title="This tooltip shows for the whole div!">This div has a tooltip.</div>
You can easily change their style by modifying the CSS, and can feel free to make any modifications you want. Demos and more available at http://www.vertigo-project.com/projects/vtip