I made a few examples around 1 - 2 weeks ago, although I don't see the tooltip it shows, you can check this out:
http://nile.richei.net/applets/tooltip/
If you go to this:
http://nile.richei.net/applets/tooltip/toolt.js
You can see all the javascript I used, the first part are arrays, as you can see:
toolt[0] = "The username is needed for your login details. When you login you will want to use this.";
toolt[1] = "The password is a secure random input that should be kept safe.";
toolt[2] = "The definition of \"Mutilated\", is broken. \"That toy is mutilated\"";
toolt[3] = "This is in a really big area. This can be useful for info that you want to provide";
You can make more, or delete some of these.
When you want the hover effect to affect. You put this on the link/button:
onMouseMove="showtooltip(x,'tooltip',event)" onMouseOut="hidetooltip('tooltip')"
I made the highlighted above, thats where you put the number of the array(toolt) you want to display.
You also need to include this on your page:
<div id="tooltip" class="toolt"></div>
Hope this Helps,
Nile