Skype only provides Fedora-specific RPM's for Fedora 6 or 7. Usually these work on FC 8, but that's not a necessity. You could also install the shared or static Skype packages, maybe even the OSS version (all others use the ALSA audio system).
If it doesn't work by default, then tracing the problem can become extremely difficult. I have a Fedora 8 box that had a working Skype setup, then somehow it broke (I suspect Xine has to do with it) even without any hardware or Skype installation changes. So far I didn't had the nerves to hunt down the problem. Prepare for quite some wasted hours, before getting some results.