Shoutbox

I think that you may be looking at this the wrong way.  Instead of parsing your site to extract the text from a specific <div> it may be much simpler to have your site provide the same text in a more handy format, such as a .txt file or a web service.  If it is "your" site, you should have the ability to set this up.

If it isn't your site, the functionality you are talking about is called "web scraping" and looking that up may yield some helpful information.