URL Snooper is quite simple to use. It finds the URL of such streaming audio and video by watching network traffic to your computer. It is also able to intelligently complete the URL if the website just shows relative URL.
URL Snooper also provides filters to intelligently show URLs related to media files. So, you can quickly see the URLs that you are interested in.
URL Snooper uses freeware WinPcap to monitor network traffic. Then it intelligently extracts relevant information from that, and shows you the hidden URLs.
URL Snooper is easy to use, and completely free. Download URL Snooper free.