Hovercard is a free light weight jQuery plugin that enables you to display related information with the hovered label, link, or any html element of your choice. It comes with built in Twitter and Facebook hovercard.
A hovercard comes handy when displaying Person bio, Book author and price, Loading related information with Ajax and Editing in place. You may also add your own custom data source and display the profile data using existing card format. It supports callback functions on hover in and hover out.
Tooltips | License Free