Many URL Finders for Windows use WinPCap. It seems that libpcap is used in Linux instead. libpcap is a system-independent interface for user-level packet capture. libpcap provides a portable framework for low-level network monitoring. There should be at least applications using libpcap that can find stream URLs.

Haven't tried any URL Sniffers / URL Finder for Linux yet, so I don't really know whether there is something as handy as URL Snooper for Windows. Please let us know if you find anything.

p.s.
I'm still using streaming media recorders for Windows. I run them either with Wine emulator or on a virtual machine with Windows XP.