Looking for code I know I found before for a hover over text.

Hey just wondering if anyone here knows of where to find code I know I saw before but can't seem to find now and heck can't recall if it's dhtml or java or just reg html....

I need to have a text box pop up when you hover your mouse over a word like how trillian does it with def's for certain words and what not just for html. Know I've seen it before. I don't want a annoying windows box pop up or anything like that just a small box to appear until the mouse moves away from the word.

Once again I reiterate I am not looking for a popup window. Just a small simple box hovers till you move your mouse away.