I released my ShoutBox for Mambo today. With it users of your page can leave small messages to other visitors. It features:

• Shows the last 20 messages in a box.
• Shows the users name if he is registered.
• Features 14 smilies with easy click-in.
• Automatically removes bad html code.
• Detects URL's and E-Mails.
• Refreshed every 60 seconds.
• Admin can clear it with a click.

But please consider it as beta state. It currently only works for newer browsers that support the iframe tag. Older browsers will be included in an upcoming version. Code is already in, but not yet running. You can download it from the filebase.