FCEUX is a solid NES emulator, and today I found out that it builds pretty well on OS X. (It requires X11 or Xquartz.) I'll be
posting the latest builds, but it's pretty easy to get up and running using Homebrew:
Install
Homebrew (requires you to install the OS X developer tools)
Run the following in Terminal:
brew install http://xannode.com/fceux.rb
For MacPorts or Fink, I think you only need SDL and libz. I couldn't get the latest release to build, but the latest SVN worked fine.
Double-clicking the fceux binary worked for me, and you can package it by throwing it in FCEUX.app/Contents/MacOS (you'll need to make these folders).
I just thought I'd spread the word! It's not Mac-native like
Macifom, but it's another option for NES emulation on the Mac.