'Twasn't simple, but I did finally get it all to work.

Firstly, for the mpeg2enc.intel component, one trick is that if you click the link & get a page of symbols, select all and "Save Page As" (under File) to your desktop & you will have the file. The additional trick for me then was that because it ends in ".intel" (which is not *exactly* what ffmpegX is looking for) it refused to accept the file. Delete the ".intel" from its name, and that one should be good to go.

Next, to get the mencoder and mplayer components, you can download them directly from here: http://www.mplayerhq.hu/design7/dload.html (or link here: http://www.videohelp.com/tools/MPlayer) go to the first group of downloads (Binary Codec Packages) and select a download http for your region and platform (in my case, Mac OS X x86 20060611/ in the US) -- note also: for me this worked when I selected to have the file automatically unzipped. In the resulting downloaded folder are the two components, mencoder and mplayer. Move them directly to your desktop.

Now, in ffmpegX (if needed, you can bring up the installation menu again from under ffmpgX>Install binaries) be sure to first enter your login password, or it won't let you locate anything. Then locate each of the above 3 components -- again, they should be all right on your desktop -- and voilá, they finally all should locate & install.

Took much searching and frustration, but at last success.

(Note too that apparently if you've managed to install components from previous attempts, and they didn't work, you'll need to uninstall them first -- use Spotlight -- not relevant in my case as I was unable to previously get anything to install) Good luck.