jTip is a super simple tip plugin, it's so simple we only have 4 options to use. Which attribute, that class for the tip, and the coordinates away from the element.
Cut & Paste Ajax Tooltip script v1.2
Script that enhances the default "title" attribute of HTML so certain tooltips can instead get their contents from an external file, with rich HTML content and all. Integration is easy and non obtrus ...
JS Cool Tips
Making an Interactive Picture with jQuery
How to piece together an interactive picture, aka an image that contains tooltips and popup boxes.
Prototype Window Class : Introduction
Prototip 2 - Create beautiful tooltips with ease