as most stations nowadays use Flash for their website players programmes like Roku Radio Snooper or similar software are no longer of any use. Stations, however, that want you to know the stream URLs usually publish them on their website.
Using a packet sniffer like Wireshark
might help in many cases but finding the URLs in the massive amount of data these sniffers collect can be tedious.
Your best choice therefore is to have a look at the stations' websites (sometimes examining the HTML code of the player page will be helpful) or search for the stations in directories like Radio Roku
If all you need is a handful of stream URLs please feel free to post the stations' names here and I'll see what I can do.