Hyperlink tooltip box

If you are using Visual Studio 2005 you can you the AJAX animation extender control. A tutorial about this control is available at
http://www.asp.net/learn/videos/view.aspx?tabid=63&id=117

If you are not using VS 2005 you may want to go to the JavaScript forum and post a question on how to create this tooltip box using javascript. Then on your hover event of your hyperlink you will call the javascript function to show the tooltip box.