Chatbox in js and php

Hi I need a chat box with my customers as they have on: koolprint dt co dt uk It needs to work on the customer side as they have it there. On the admin side I want that as soon as a customer types in a question a popup opens on my side with a sound so my reps become aware of the new customer requiring info. In the popup I also want to see some info, like cookies data and the URL the customer currently is on. The whole thing in php 4 and js, in case a database is required then please use mysql 4.x This should be based on existing libraries (for cost) and be as simple as possible for maintenance reasons thx for your bids