I am in file dependency hell. I'm trying to install xine, which worked on my old system, but when I try from a tarball or an RPM using rpm -i, some of those needed files I can't find anywhere. I looked for them in sourceforge, all the RPM sites, and a straight googe search. I've heard that yum might solve file dependencies, but when I run yum install,
it says I need a gpg key. So I got it. The executable is in /usr/bin/gpg, so it should work, but I don't know how to use it. Yes, I read the man pages, but that didn't help. When I type just "gpg" it says "go ahead and type your message", but it won't do anything with any install commands. What am I doing wrong?

You need to import the GPG key from the repo you are trying to use, e.g.

rpm --import http://mirrors.kernel.org/fedora/cor...GPG-KEY-fedora

This is for FC6 -- you can find a key for anything else by looking around -- the key for FC3 is the same URL as above with the 6 replaced by a 3. Newer Yum versions offer to import the key for you automatically but IIRC the one in FC3 does not so you have to do it by hand with the rpm --import command.