This is a little HOW-TO I posted on the "Mac OS X Wiki" for the Gamecube/Wii emulator called "Dolphin"
http://www.dolphin-emu.com/

Be aware that for Mac OS X it's quite slow (it runned Zelda WW with 12/13 fps on my old iMac 24" (2008), but on Snow Leopard
it seems even slower...

If some Mac Developers want to help to optimize Dolphin on the Mac that would be great!

You can even build a non-GUI version, ideal for porting to Cocoa :-)
Anyway try yourself and let me know ;-)

How to compile Dolphin-svn for Mac OS X 10.6.x Snow Leopard with Macport's wxWidgets 2.8.9
Also on: http://code.google.com/p/dolphin-emu/wiki/MacOSX_Build

0. You need at least an INTEL Mac and a fast graphic-card (so MacMini and Macbooks = no go)

1. You need Apple Developer Tools XCode 3.2.1. Download freely from http://connect.apple.com
2. You have the latest nvidia cgtoolkit installed from http://developer.nvidia.com/object/cg_download.html
3. If you have installed Macports before, I would suggest to uninstall the installed ports. See this page how to do it:

http://trac.macports.org/wiki/Migration

4. Download and install the latest Macports 1.8.2 for Snow Leopard:

http://distfiles.macports.org/MacPorts/

5. Snow Leopard users: this step is necessary to succesfully build and install wxWidgets 2.8.9 from macports.

If you have Snow Leopard 10.6.x fire up your favorite editor (Textwrangler 3.1 is free :-) and add the line '+universal' to macports file /opt/local/etc/macports/variants.conf

Or you can add it via Terminal with this command:

 # echo +universal | sudo tee -a /opt/local/etc/macports/variants.conf

6. Launch and update your Macports tree from Terminal:

# sudo port selfupdate

7. Install the required ports to compile Dolphin (this will take some time to compile)

# sudo port install wxwidgets libsdl cairo scons glew subversion

8. Checkout the latest dolphin-emu svn release to your Downloads directory, with subversion:

#/opt/local/bin/svn checkout http://dolphin-emu.googlecode.com/svn/trunk/ ~/Downloads/dolphin-emu-read-only

9. After it has finished to download the latest svn version, go to the directory and launch compilation with command 'scons'. In fact the 'scons' application (written in Python) reads the file SConstruct file to compile

#scons verbose=yes

9b. You can even switch Open CL on with to get better performance:

#scons verbose=yes opencl=true

By default Dolphin will build in 32bit mode. If your Snow Leopard Kernel is 64bit, which is not the case for most Snow Leopard users then you should compile with command.

#scons osx=64cocoa opencl=true

10. After succesful compilation launch the application Dolphin.app from the folder ~/Downloads/dolphin-emu-read-only/Binary/Darwin-i386/

Notes Dolphin's config files are installed in your Home's folder > Library > Application Support > User ~/Library/Application Support/Dolphin/User

The most important config files are in the "Config" directory, which you can alter less or more via the "Config" button in Dolphin,
but it's better to edit them via your favorite editor:

Dolphin.ini
DSP.ini
gfx_opengl.ini

Open them in your favorite editor and try the various parameters to tweak Dolphin.

Please let me know if something's wrong. Hope this helps ;-)