dynamic html "more information" callout / annotation (jquery? ajax control toolkit?)

Hola, I have an app i'm building in c#, and i'd like to have the ability to have a user click a "more information" icon next to a field, which will then show a callout with some blurb about why the field contains what it does.

ideally it'd look a lot like the ValidatorCallout, but instead of being shown as a result of validation, it'll be shown as a result of a mouseclick, or hover.

Anyone know of a nice way to do this with either the ajaxcontroltoolkit开发者_开发百科, or jquery?

cheers for any help you can give me.

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Maybe these links helps:

http://updatepanel.net/2009/04/19/jquery-aspnet-validator-callout-plugin/

http://wiki.jqueryui.com/Tooltip