yes this is possible.... you are most undoubtably using an iframe for your chat box right? well if you are all you need to do is just make a link somewhere on the page with a link to your chat box something like so
Code:
<a href="URL_TO_CHAT" target="_blank">Chat Box</a>
... if you want to get a tiny bit fancy you can make it so that the new page is not the same dimensions as a regular page he / she is viewing... to that you need a tiny bit of javascript.
Code:
<a href="#" onclick="window.open('URL_TO_CHAT','_blank','width='WIDTH_OF_CHATBOX',height='HEIGHT_OF_CHATBOX,directories=no,location=no,status=no,menubar=no,toolbar=no,scrollbars=no,resizable=no')">Chatbox</a>
then all you would need to do is just fool around width the right height and width settings to what fits your needs.
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