How to determine the url of a radio stream

I have this annoying little problem where I find and internet live
radio on a web site and would need to determine the actual url so that
I don't have to fire up a browser every time I want to listen to that
particular radio.

So etimes a simple wget of the link that invokes the mplayer plugin
followed by a quick browse of the page's content are sufficient.

But some sites appear to hide the mms://.... under triple layers of
javascript so that it can be difficult to figure out the url.

The mplayer plugin is not much help either since it does not show
anything apart from the start/stop/pause buttons.

And all I can see via a pstree is that the plugin starts two mplayer
processes in "slave" mode .. but not trace of the actual url.

I have tried playing a bit with such tools as netstat, tcpdump, etc.
but have not been able to really find much of anything.

Is there a tool that would be more adapted to this?

Or do I really have to read relevant documentation and learn the gory
details about mms before I can go any further?

Thanks,
cga