You would need some sort of
javascript popup code. There are a couple of ways to add it, it will most likely need an onload statement of some sort which you can add to your default header and then the link code which can be added to your ubbt_registered (and unregistered if you want) tmpl files depending on if you want the users to click to launch or whether you want it to popup on them.
Often times you will have to modify the javascript because of conflicts with all that is going on with threads, it will take some playing with your environment. Then you can add whatever sound code you want to your popup window. Is all this general enough for you
