How can you do screen tips in html?

For example, on Yahoo's homepage, when you hover over the link to "My Yahoo", a small box appears saying, "Go to My Yahoo"...can that sort of tip/pop-up be done with basic html? If so, what is the code?

Anonymous2006-07-10T13:13:27Z

Favorite Answer

in an html tag you put title="your message here". for example

<a href="
http://www.yahoo.com/"
title="your message here">
yahoo</a>

title works like alt attribute in an image tag.

Anonymous2006-07-10T13:08:24Z

those 'popup' items appear when you hover over an image with Text in the "ALT" attribute.

For example: <img id=ygmalogo src=http://us.i1.yimg.com/us.yimg.com/i/us/sch/gr/ga_ans_uh_logo.gif width=264 height=33 border=0 alt="Yahoo! Answers">

The 'Yahoo! Answers' it the text that appears when you hover over the Yahoo! Answers logo.

John J2006-07-10T13:11:16Z

for images include an alt="copy here" value, for text just surround it in a <a title="copy here"></a> set of tags.

Anonymous2006-07-10T13:06:06Z

<a href="yoururl" title="text you want to display">