Tricks dealing with:
View movies, audio, pdfs, and other media embedded in firefox using mozplugger.
Watch streaming movies and audio embedded in firefox using xine.
What you need here is mozplugger. Really, this will work with many different browsers, just follow the install instructions in the README. After you do that, find and edit 'mozpluggerrc' to your liking (which programs to use to embed which files). NOTE: I recommend against using mplayer-plugin, simply because it is quite unstable, and will crash firefox if you have flash player 9 installed, and sometimes even on its own. Mozplugger seems to have no problems with flash player 9, so I recommend it. Mozplugger will work best for static media (non-streaming). If you want streaming media, see the next section.
For this you need the xine-mozilla-plugin. Get it and install it, I recommend from source, the '.src.rpm'. NOTE: You should not have both mozplugger and xine-mozilla-plugin installed at the same time as conflicts may occur. Usually, I install both of them locally to my ~/.mozilla directory so that I can quickly, easily, and safely switch between them at will, by simply renaming. I have one directory containing everything needed for mozplugger and another with everything for xine-mozilla-plugin, and I just rename whichever one I need at the time to 'plugins'. That's it. Again, xine-mozilla-plugin works best with streaming media.
See the scripts section for more trickery.