Pinecone has released his own DevkitPPC installer for Mac OSX Leopard for the latest release from the Devkit toolchain, r16. It is VERY untested, so please use at your own risk.

It can be downloaded from here.

What it is
The package installs the minimum you need for creating and building Wii and Gamecube apps, which includes LibOGC and some compiler trickery (don't ask me how it works: I have no idea). It also includes, as did the previous installer, an Xcode template for creating both Wii and Gamcube apps. This is all installed automatically.

http://wiibrew.org/wiki/DevkitOSXInstaller